The Mutants

Original Airdate: 8 Apr, 1972

Episode One

[Solos]

(An old man dressed in rags and with a huge grey beard is making his way through the scrubby vegetation, half hidden by the mist. He is out of breath and frightened.)
MARSHAL [OC]: Over here! Move in! Path! He's heading to the path! This way! Over here!
(A slightly portly man in black uniform with silver trim, helmet and breathing mask is carrying a device which is bleeping. He rips off the mask and shouts.)
MARSHAL: Mutt! Mutt! Hurry, you men. Hurry! Mutt!
(The mist clears to reveal the old man a little way ahead. The Marshal gives chase, dropping his mask. One of his men picks it up.)
STUBBS: Sir! Marshal, your mask!
COTTON: (a dark man) Mutt mad he is. Sport to him.
STUBBS: Kill one before he passes out.
COTTON: Solos. Stinking rotten hole. Can't even breathe. What a planet.
STUBBS: Not long now, soldier.
COTTON: Should have given them independence years ago.
(The old man lies face down by a muddy. There are two rows of protuberances down his spine.)
MARSHAL: Look at it. Disgusting mess. Get rid of it.
STUBBS: Sir.
MARSHAL: Make out a report. Mutt found dead, as usual.
(The Marshal moves away and Stubbs pulls a communicator from the front of his uniform.)
STUBBS: Stubbs calling Skybase. Returning shortly. ETA forty two zero six. Have dealt with mutant native alert, area seven. Mutant tracked and found dead on arrival. Cause unknown.

[UNIT Laboratory]

(The Doctor is working on a small electronic module.)
JO: Doctor?
DOCTOR: Mmm?
JO: Are you going to be very much longer?
DOCTOR: No, nearly finished, Jo.
JO: What are you doing anyway?
DOCTOR: I'm making a minimum inertia superdrive for Bessie.
JO: Oh. Well, for your information, it's well past lunch time, and I'm
DOCTOR: Eh?
(What looks like a very large chocolate Easter egg materialises on the workbench.)
DOCTOR: Oh dear, oh dear, oh dear.
JO: Lunch?
DOCTOR: No.
JO: Bomb?
DOCTOR: No, nothing so exciting.
JO: Well?
DOCTOR: It's an assignment.
JO: Well then, it is exciting.
DOCTOR: No, it's a container of some kind, Jo, from them.
JO: Time Lords?
DOCTOR: That's right.
JO: Well, aren't you going to open it?
DOCTOR: I'm not allowed to open it.
JO: Huh?
DOCTOR: I couldn't, even if I wanted to. No, I'm not meant to. I couldn't open it, even if I wanted to. No, it's only meant for one person, and or creature. It will only open for one person.
JO: And or creature.
DOCTOR: Yeah, that's right. Yes, I'm just the messenger boy.
JO: Well, can't you just refuse?
DOCTOR: They only send these things in a real emergency, Jo. It's top priority, a three line whip. No, I've got to go.
JO: How do you know where to deliver it?
(The Tardis roof light flashes and she starts humming with energy. The door opens on its own.)
DOCTOR: I think that has already been decided.
JO: Hang on, wait for me. I'm coming too.
DOCTOR: That's out of the question. It's bound to be dangerous, probably difficult.
JO: All the more reason. You need me to look after you.
DOCTOR: Sorry, Jo, a lot of rubbish. Not this time. Au revoir!
(The Doctor enters the Tardis.)
JO: Oh, no you don't!
(Jo runs into the Tardis before the door can close. The Tardis dematerialises.)

[Skybase One storage room]

(A large spaceship that looks like the front part of Discovery, the spaceship in 2001, orbits the planet Solos. The Tardis materialises in a quiet room containing a few white storage units, and with one large blue oval door in the wall.)
JO: Well, where are we?
DOCTOR: It looks like the tradesman's entrance, doesn't it.
JO: What do you mean?
DOCTOR: I don't see any red carpet, do you?
(Jo looks through a small porthole.)
JO: Doctor, look. We're flying.
(They gaze down at the white, cloud covered planet with a few mountain peaks pushing through.)
DOCTOR: We're not exactly flying, Jo. We're in planetary orbit. We must be on a
(A klaxon sounds.)
MAN [OC]: Skybase One. This is Skybase One.
DOCTOR: A Skybase.
JO: Amazing.
MAN [OC]: Duty personnel to reception and transfer section. Clear visiting party.
DOCTOR: We are expected then.
MAN [OC]: Next, escort them through bacteriological decontamination hall. Skybase One out.
JO: Bacteria what?
DOCTOR: Well, put less delicately, Jo, delousing.
JO: Cheek.

[Skybase One transfer section]

(A man in Mongol-type armour and clothing comes out of a doorway labelled Solonians and is greeted by another of his kind. Another doorway is labelled Overlords. Black uniformed guards stand around.)
VARAN JR: Father.
(The Solonian doorway glows blue and another man in less armour comes out.)
VARAN: Greetings, Ky.
KY: I knew you would be here, Varan, with your Overlord masters.
VARAN: And why are you here?
KY: I was summoned.
VARAN: You will attend the conference?
KY: The conference? More lies from the Overlords. More promises of freedom.
VARAN: Yet Ky still came?
KY: I came to demand that the Overlords stop murdering our people.
VARAN: The mutants must be rooted out. They are evil and diseased.
KY: Who tells us that?
VARAN: My eyes tell me.
KY: No, Varan, the Overlords tell you. They tell you to kill and you kill.
VARAN: My people are warriors. It is honourable to fight.
KY: Where is the honour in hunting down unarmed creatures?
VARAN: It is their duty, Ky. They are diseased.
KY: If it is a disease, what has caused it? Once we were farmers and hunters. The land was green, the rivers ran clear, the air was sweet to breathe. And then the Overlords came, bringing Earth's poisons with them, calling it progress. We toiled in their mines, we became slaves. Worse than slaves!
VARAN: Liar!
KY: Murderer! You have nothing else to hunt, so you hunt your own kind.
(Ky and Varan square up to fight. Varan reaches for his sword and a guard intervenes.)
STUBBS: So you've arrived, Ky.
KY: As you see, Overlord. We come when we are called.
STUBBS: Well, don't just stand there making speeches, get into decontamination.
(Stubbs indicates an area through a large archway.)
STUBBS: And the rest of you. Varan, the Marshal wants to see you.
(Varan's bodyguard makes to follow his leader through a second archway.)
STUBBS: Alone.
VARAN: Wait.
(Varan leaves. Stubbs leaves down a corridor past Decontamination. A guard moves over to the bodyguard and grabs his arm. The bodyguard does not have a normal hand.)
GUARD: Mutt!
(The bodyguard knocks out the guard and makes his escape.)

[Skybase One storage room]

DOCTOR: Taking their time, aren't they, Jo? Jo? Jo, where? Oh, they you are.
(Jo comes from behind the Tardis.)
JO: Doctor?
DOCTOR: Mmm?
JO: Are you sure we're in the reception area? Looks more like a broom cupboard. Where exactly are we, time wise?
DOCTOR: Don't use expressions like that, Jo, please.
JO: All right, century wise.
DOCTOR: According to the Tardis's instrument readings, we are now in the thirtieth century empire.
JO: I see. What empire?
DOCTOR: Your empire. Earth's empire. Yes, great colonists, Earthmen, you know, Jo. Once they'd sacked the solar system, they moved onto pastures new. Solos is one of them. One of the last. Did you ever read Gibbon's Decline and Fall?
JO: No. Is it good?
DOCTOR: Jo, this is like that. You see?
JO: No.
DOCTOR: Oh. Well, empires rise and empires fall. And if this is their idea of a reception, this one has obviously crumbled.
(The Doctor goes to the door. On the left is a panel with a hand print on it.)
DOCTOR: Right, if we're to get out of here, I've obviously got to try and break the circuit.
(The Doctor takes out his sonic screwdriver.)

[Marshal's office]

(Varan enters with two guards.)
MARSHAL: Ah, Varan.
VARAN: Why has Ky been summoned to this conference?
MARSHAL: Oh, you've seen him then.
VARAN: He called me murderer. Me, Varan. I should have finished with him there and then.
MARSHAL: Oh no, Varan. We want no martyrs. I have other plans for Ky.
VARAN: You said I would represent my people.
MARSHAL: You will be there. You and Ky. Now listen.

[Skybase One storage room]

(The sonic screwdriver burns out the lock and the door opens.)
JO: The box.
DOCTOR: What?
JO: The box!
DOCTOR: Oh yes, of course.
(The Doctor fetches the egg from the Tardis.)
DOCTOR: Here, you take it.
JO: All right.

[Storage area 4]

(According to the sign on the wall.)
DOCTOR: It's all right, there's nobody about. Come on.
(The klaxon sounds.)
MAN [OC]: Attention. Attention. Computer confirms door malfunction in storage area four.
JO: That's us.
MAN [OC]: Investigation please.
DOCTOR: Yes, I know. I'm not sure I like being described as a malfunction.

[Storage area 5]

(A game of chess is ongoing. The pieces are metal tubes with decorated tops. Cotton is playing black, or copper actually.)
COTTON: Check.
MAN [OC]: I repeat. Investigation please.
STUBBS: That's us.
COTTON: What is it?
STUBBS: A door.
COTTON: Door? All the way over there for a door?
STUBBS: Yeah, seems a bit pointless, doesn't it.
COTTON: Ah, leave it. Leave it till morning. We have only just got back up here after that Mutt hunt. Tell you what.
STUBBS: What?
COTTON: You won't catch him rushing about tonight.
STUBBS: Who?
COTTON: His Nibs. The Marshal.

[Marshal's office]

MARSHAL: Understand? I want a man I can trust, trust absolutely.
VARAN: All my warriors can be trusted. They will fight to the death for Varan.
MARSHAL: Then you will need this pass.
(The Marshal gives Varan a red plastic chip.)
VARAN: It is good.
MARSHAL: Huh. I doubt if Ky will think so. Varan, I shall want to see this man of yours myself.
VARAN: Now?
MARSHAL: Afterwards.
(Varan leaves.)
MARSHAL: The fool.

[Skybase One corridor]

DOCTOR: Hello? Hello?
(They walk into storage area 3 and the Doctor tries a door panel. Nothing happens so he gets out the screwdriver.)
JO: Doctor.
DOCTOR: Well, we can't wander around here all night with nobody noticing, now can we?
JO: Doctor, look!
(It is the bodyguard. He draws his sword and rushes forward just as the Doctor gets the door open and goes through followed by Jo. The bodyguard's arm is trapped by the closing door.)
MAN [OC]: Attention. Attention.

[Storage area 5]

MAN [OC]: Door malfunction in storage area three. Immediate investigation ordered. Possible emergency. Out.
STUBBS: We should have gone the first time. Come on.
COTTON: Oh, we couldn't have known.
STUBBS: Come on! We're in enough trouble already. Two malfunctions, eh? I don't like the sound of that.

[Storage area 3]

(The bodyguard's arm is flailing around as the Doctor tries to hold the door shut.)
DOCTOR: I can't hold it much longer.
JO: Well, what is it?
DOCTOR: I've no idea but whatever it is, it isn't friendly!
(Stubbs and Cotton enter through another door.)
STUBBS: Away from that door.
DOCTOR: Look, you fool.
STUBBS: Away from the door!
DOCTOR: Look at his hand!
(Cotton pushes the Doctor and Jo away. The bodyguard enters, roars and Stubbs shoots him.)
STUBBS: (into comm.) Stubbs and Cotton investigating malfunction storage area three. Mutant native contacted and destroyed. Two other non-personnel found and held. Report ends. Good evening, sir. Will you please come with us to reception?
DOCTOR: I assume I have no choice?
STUBBS: This way, sir.
DOCTOR: Mutant native, you said?
STUBBS: That's right, sir.
(The bodyguard also has the ridges down his spine.)

[Marshal's office]

MARSHAL: (into comm.) A mutt? On my Skybase? How?
STUBBS [OC]: He was Varan's bodyguard, sir.
MARSHAL: Varan's bodyguard? Get me a full report at once. Hold the other two, and get Varan.
(The Marshal's communicator is the top of his swagger stick. He shuts it off as a man in a long black coat enters.)
MARSHAL: I've asked for a full report, Administrator.
ADMINISTRATOR: I should think so. What happened to your security arrangements? And why wasn't I informed that Varan was here? Really, Marshal, on the eve of the independence conference. (Everyone say Hi! to Geoffrey Palmer.)
MARSHAL: They'll be a full security clampdown. The Solonians will never know. As for Varan, he was merely reporting on Ky's activities.
ADMINISTRATOR: Spying for you, you mean.
MARSHAL: All part of security.
ADMINISTRATOR: Security? Such as we had tonight? Natives and the devil knows who else running amok. Good heavens, man, we're not at war with the Solonians. We're giving them independence.
MARSHAL: Oh, eventually.
ADMINISTRATOR: Not eventually, Marshal, now. Total and absolute independence. We're pulling out.
MARSHAL: Pulling out?
ADMINISTRATOR: I take it you've been too busy with security to study the latest reports from Earth? We can't afford an empire any more. Earth is exhausted, Marshal. Finished. Politically, economically and biologically finished.
MARSHAL: Then why go back? We could keep Skybase on Solos, take over the whole planet.
ADMINISTRATOR: Out of the question. Apart from the Solonians themselves, there's the problem of the atmosphere.
MARSHAL: Well, they're both problems that can be solved.
ADMINISTRATOR: Ky's already making political capital out of your experiments in that field.
MARSHAL: The mutants.
ADMINISTRATOR: Exactly.
MARSHAL: There is no proof that my atmospheric experiments have anything at all to do with these mutations. The Mutts are a menace and must be wiped out.
ADMINISTRATOR: And that's your alternative to independence? Genocide?
MARSHAL: Give them independence, they'll starve out of total incompetence.
ADMINISTRATOR: Nevertheless, they shall have their independence. Whether they're ready for it or not.
MARSHAL: When you summoned this conference, Administrator, I assumed it for your usual line.
ADMINISTRATOR: Which is?
MARSHAL: Fob them off with promises, a few minor concessions. It's always worked before.
ADMINISTRATOR: Well, this time I'm conceding all Ky's demands.
MARSHAL: But
ADMINISTRATOR: We have no choice. We must return to Earth.
MARSHAL: But I've put years of my life into this planet. The whole, my whole career
ADMINISTRATOR: Yeah, well, I'm afraid things are going to be a bit tricky for ex-colonial officials. Still, don't worry, old chap. We'll find you something. The Bureau of Records, perhaps. Something clerical.
(The Administrator leaves.)
MARSHAL: (into comm.) Get me that fool, Varan.

[Skybase One room]

(Jo is looking through a porthole, and wearing sunglasses.)
JO: Doctor?
DOCTOR: What?
JO: You can see the planet in daylight now.
DOCTOR: Oh, yes, so you can.
JO: It's not like our Earth, is it? It's all grey and misty.
DOCTOR: Well, the Earth these people know now, Jo, in the thirtieth century empire, is even more grey and misty.
JO: It can't be!
DOCTOR: Land and sea alike, all grey. Grey cities linked by grey highways across grey deserts.
JO: Really?
DOCTOR: Oh, yeah. Slag, ash, clinker. The fruits of technology, Jo.
(Stubbs steps aside as the door opens and the Administrator enters.)
ADMINISTRATOR: Morning.
DOCTOR: Good morning.
ADMINISTRATOR: I've seen your statements. What is it you want? As briefly as possible.
DOCTOR: We come from Earth.
ADMINISTRATOR: Who sent you?
DOCTOR: Overlord Centre.
ADMINISTRATOR: The council, you mean?
DOCTOR: Yes.
ADMINISTRATOR: The council has no further interest in Solos.
(The Marshal enters.)
DOCTOR: Well, they certainly had when we left.
MARSHAL: Just, er, when did you leave, Doctor?
DOCTOR: Sometime ago now.
MARSHAL: He's lying. He's got no pass.
DOCTOR: Look, this was an emergency.
MARSHAL: There have been no shuttles, no departures from Earth, no arrivals on Skybase in weeks.
DOCTOR: For goodness sake, does it matter how we got here?
MARSHAL: They must be from Solos.
ADMINISTRATOR: Let him speak. Why are you here?
DOCTOR: This is why. Jo?
(Jo hands the egg to the Doctor who hands it to the Administrator. Nothing happens.)
DOCTOR: Yes, well, obviously it's not for you.
(The Marshal takes it. Also nothing.)
DOCTOR: Nor you, it would seem.
ADMINISTRATOR: Is this some kind of joke? Who is it for? What is it, anyway?
DOCTOR: Well, it's a container of some kind, but I must have confess that I
ADMINISTRATOR: Then open it!
DOCTOR: I can't.
(The Marshal takes Stubbs' weapon.)
MARSHAL: Open it!
DOCTOR: You're wasting your time, Marshal. This box will only open for the person to whom it was sent.
MARSHAL: We shall see. Stubbs?
STUBBS: Sir.
(Stubbs places the egg on a display stand.)
MARSHAL: Stand back.
(The Marshal shoots at the egg, twice. It glows and smokes then returns to dark brown again.)
DOCTOR: You see?
ADMINISTRATOR: You must know who it's for.
MARSHAL: They were found with the Mutt. They must be saboteurs.
DOCTOR: Oh, don't be a fool. If we were saboteurs, that'd be a bomb, and thanks to you we'd all be blown to smithereens by now.
(Cotton enters.)
COTTON: Sir, the Solonian delegates are ready for you.
ADMINISTRATOR: Thank you.
(Cotton leaves.)
ADMINISTRATOR: Well, whatever it is, it'll have to wait. Marshal?
MARSHAL: Be with you in a moment.
(The Administrator leaves.)
MARSHAL: Now, perhaps you'll tell me just what this is really all about.
JO: But he has! What he told you was the truth.
MARSHAL: What are you? Some sort of special agent for the council sent to check on me?
DOCTOR: If you really want to find out what's in this box
MARSHAL: I shall find out.
DOCTOR: May I suggest that you take it to the conference. It could well be for someone there.
MARSHAL: Could it? I think there are more important things. Far more important things. Stubbs!
STUBBS: Sir?
MARSHAL: Don't let these two out of your sight.
STUBBS: Sir.

[Marshal's office]

(The Marshal enters, wearing a silver waistcoat over his uniform. The Solonians are gathered around a circular smoked glass table. The guards at the door frisk Varan's son. The Marshal goes to Varan and they talk with their backs to the others.)
MARSHAL: Which is he?
VARAN: By the door.
MARSHAL: Does he understand the new instructions?
VARAN: He understands.
MARSHAL: Is he reliable?
VARAN: He is my son.
MARSHAL: Your son?
VARAN: You asked for someone in whom we could trust.
MARSHAL: Yes. Good, Varan.
(The Marshal hands Varan a small brown object on a thong, which Varan puts round his son's neck. The Marshal goes to his desk.)
MAN [OC]: His Excellency the Administrator.
(The Administrator enters wearing a very long silver and brown cape over his uniform.)

[Skybase One room]

(The Doctor, Jo and Stubbs are watching proceedings on a crystal ball which is now on the stand.)
MAN [OC]: Skybase One. Skybase One. This is an Overlord telecast.
(An anthem plays.)
DOCTOR: Bombastic signature tune, isn't it?
STUBBS: Well, it always impresses them on Solos.
DOCTOR: Does it really.
MAN [OC]: His Excellency the Administrator, is about to make his final statement of terms relating to the question of independence in the presence of the Solonian All Peoples Union.
DOCTOR: What's your view, Stubbs?
STUBBS: Independence? Oh yeah, the sooner the better. Let's get off and home. Plenty to sort out there.
DOCTOR: Yes, quite so.
(The Doctor gestures Jo to keep Stubbs talking.)
JO: Have you got a family back on Earth?
STUBBS: Oh, I hope so, Miss.
JO: Do you hear from them very often?
STUBBS: Oh, I get reports, you know. The odd video.
JO: No letters?
STUBBS: Letters?
JO: Mmm.
STUBBS: What the
(The Doctor sneaks behind Stubbs and uses a pressure point hold to knock him out.)
DOCTOR: Sorry about that, Stubbs. Well done, Jo, you did that beautifully.
JO: Pity. He was rather sweet.
DOCTOR: Do you think so?
JO: Mmm.
DOCTOR: Come on, let's get to that conference.
JO: Here, you take that.

[Marshal's office]

ADMINISTRATOR: Some five hundred years ago, we Earthmen, Overlords, as you call us, arrived on Solos. Our ancestors, yours and mine, made a solemn treaty. A pact, a bond, an act of friendship
KY: Treachery
ADMINISTRATOR: And mutual co-operation between our two peoples. A bold concept. Two different cultures, far apart in terms of development
(The Marshal nods at Varan Junior, who examines the thing hanging round his neck.)
ADMINISTRATOR: Uniting together to create a new society, a new and richer world. Now, after five hundred years of
KY: Exploitation.
ADMINISTRATOR: Expert scientific and technical aid, we have steered you to the verge of
KY: Disaster!
ADMINISTRATOR: To the verge of independence.

[Skybase One transfer section]

DOCTOR: Segregation.
JO: Hmm.

[Marshal's office]

ADMINISTRATOR: Rights and privileges as citizens of empire. You, the peoples of Solos, have given us much. And we in return have given you
KY: Mutts!
ADMINISTRATOR: A strong and stable system of government.
KY: (sotto) Freedom now!
ADMINISTRATOR: Despite
(Ky whispers to the other Solonians round the table.)
ADMINISTRATOR: Despite, I say, recent acts of terrorism, violence and subversion.
SOLONIANS: Freedom. Freedom. Freedom.
ADMINISTRATOR: The only black mark on the history of amicable relations unparalleled throughout the empire!
KY: We want freedom and we want it now!

[Outside the Marshal's office]

(Cotton is standing guard.)
COTTON: Where do you think you're going?
DOCTOR: Well, to the conference, of course.
COTTON: Not without a pass. Sorry, sir.
DOCTOR: Pass, what pass?
COTTON: Nobody in without a pass, sir.
DOCTOR: Look, all this has been arranged by the Administrator.
COTTON: Sorry, sir. That Mutt. Extra security all over.
DOCTOR: Look, this thing contains important documents. Details of the whole independence agreement, ready for signing.
COTTON: Open it up, please, sir.
DOCTOR: What?
COTTON: Can't risk weapons in there, sir.

[Marshal's office]

(Varan Junior is surreptitiously pointing the object at the Administrator, or is it at Ky?)
ADMINISTRATOR: Now it is my duty to set out the final conditions that Earth Council has laid down.
KY: Do you hear that, Varan? Hundreds of years of oppression and slavery.
ADMINISTRATOR: Good friends, I beg you to listen.
KY: (Shouts.) You pollute the lands we live by!
ADMINISTRATOR: We have no need to quarrel.
KY: Now you want to take from us the very air we breathe!
ADMINISTRATOR: Look, Earth government
MARSHAL: Guards, arrest him!
ADMINISTRATOR: Earth Government is prepared to concede if you will only let me finish!
(The guards grab Ky. There's a whiz bang and the Administrator clutches his jaw.)
KY: Out! Go!
MARSHAL: Stop him!
KY: Get back to Solos!
MARSHAL: Stop him!

[Outside the Marshal's office]

DOCTOR: No, I can't open it.
(The door opens and Ky pushes his way between the Doctor and Jo, touching the egg.)
KY: Out of my way, Overlord.
DOCTOR: The box, it's opening! Wait! This is for you!
JO: I'll get him, Doctor.
DOCTOR: Wait!
MARSHAL: After him! After him! He must be stopped!
(The chase is on.)

[Skybase One transfer section]

JO: Wait! Listen! I've got to talk to you! Listen!
(Ky grabs Jo and pulls her into the Solonian cubicle.)
MARSHAL [OC]: Stop him!
JO: What are you doing?
KY: They will not shoot an Overlord.
JO: But I'm not an Overlord. I've come to help you.
MARSHAL: Now, you fool! Shoot!
DOCTOR: No, you can't!
MARSHAL: I said fire!
(The guards fire. There is a bright flash, and Ky and Jo are no longer there.)

Episode Two

[Skybase One transfer section]

MARSHAL: (into comm.) Alert all ground stations. Your friend won't get far without a mask. 

[Solos transfer section]

(Just like the one on the spaceship, with the same notices. Jo and Ky are having a discussion as they materialise.)
KY: No Overlord can exist without a mask.
JO: How many more times do I have to tell you I'm not an Overlord?
(In his cubicle, a guard hears the Marshal's orders.)
MARSHAL [OC]: I want both of them. Do I make myself clear?
(The guard leaves his cubicle and a klaxon sounds.)
KY: Don't you see? You can't stay outside. The atmosphere is poisonous to you. No Overlord can exist for more than a few hours without a mask.
JO: Well, what am I going to do?
KY: You will stay here. I shall make a run for it.
JO: No, I'm coming with you.
KY: Look, I warn you. My life is more important than yours, to Solos and my people. I cannot stop to help you.
JO: I'm coming with you.
KY: Shush, guards!
(The guard enters the transfer area and Ky jumps him from behind, knocking him out.)
KY: Come on!
(Ky pulls Jo along a short passage to the airlock. The guard recovers enough to fire his weapon as they leave.)

[Airlock]

(Ky operates the outer door.)
KY: You all right?
JO: Fine so far.
KY: Good.
(They step out into the all pervasive mist.)

[Marshal's office]

DOCTOR: Bad news?
MARSHAL: Not for you, Doctor. For your friend. They have escaped on to the surface of Solos.
DOCTOR: Ah.
MARSHAL: Still, without a mask. But never fear, Doctor, we shall find her. Or her body.
DOCTOR: Would you kindly explain that remark, sir?
MARSHAL: During the hours of daylight no human can survive on Solos without an oxymask. The soil contains a nitrogen isotope unknown on Earth. The ultra-violet rays of the sun cause a kind of poisonous mist.
DOCTOR: How poisonous?
MARSHAL: I give your friend an hour, possibly less, depending on how fast they're travelling. I could, of course, step up the search.
DOCTOR: May I suggest that you do so immediately?
MARSHAL: Or I could call off the search altogether. Let them escape.
DOCTOR: And let her die? You can't do that!
MARSHAL: I can do as I please, Doctor. And since the unfortunate assassination of the Administrator, Solos is under martial law. My law.
DOCTOR: How very convenient for you. Now look, are you going to search for Miss Grant or not?
MARSHAL: That depends on you, Doctor.
DOCTOR: Does it?
MARSHAL: Well, I thought you said this box was intended for Ky?
DOCTOR: Apparently.
MARSHAL: Then I shall want to know what's in it before he does.
DOCTOR: No, I'm sorry. That would be completely unethical.
MARSHAL: Then I shall be forced to recall my men, Doctor. We're stretched very thin on Skybase. So many demands on our resources, you know.
DOCTOR: All right. I'll try and open the box for you, but I shall need your most advanced laboratory facilities.
MARSHAL: (into comm.) Calling Solos. Intensify the search.
DOCTOR: Marshal!
MARSHAL: The girl must not be harmed.
DOCTOR: That's better.

[Solos]

(Ky leads Jo at a run through the scrub until she falls, gasping for breath. He picks her up and carries her. Three guards are close behind.)
STUBBS: This way. Funny. Only one now. Only one trace registering.

[Skybase One laboratory]

(A large room with computers on the walls and catwalk around.)
MARSHAL: Well?
DOCTOR: Adequate. Not quite what I hoped for but adequate.
MARSHAL: Adequate? What do you mean adequate? It's the finest laboratory it's possible to build.
DOCTOR: Well, I was rather hoping for a particle reversal set-up. You know, something that would turn the box inside out. But all this stuff, it seems for geared for atmosphere modulation.
(They go down the steps to a large device in the middle of the lab.)
DOCTOR: And this circuit's about to overload for a start. What is it anyway, weather control?
MARSHAL: Something of the sort. Now, tell me, Doctor
(A little man in a brown uniform with a Germanic accent barges in.)
JAEGER: What the blazes is going on in here? Oh, it's you, Marshal. My apologies. But there was tampering with one of the circuits.
DOCTOR: Yes, I'm terribly sorry, I'm afraid that was me. I'd no idea that the thing was operational. One of your circuits was about to overload.
JAEGER: Marshal, I must insist! The experiment has reached a critical stage. I'm working here alone and against time and, with respect, I can't afford to have you or anyone else interfering with it whenever you feel like giving some stupid guided tour.
MARSHAL: Jaeger, that's enough.
JAEGER: You give full priority to atmospheric regeneration and then you expect me
MARSHAL: Jaeger! Jaeger! For the moment, Jaeger, I want you to give full priority to this little problem here.
JAEGER: What? What is it? Who is this man?
MARSHAL: An emissary from Earth. So he claims.
(The Marshal's comm. whistles.)
MARSHAL: Mmm?
VOICE [OC]: Varan's son's in your office, Marshal.
MARSHAL: (into comm.) Good. Hold him there. I'm sorry, gentlemen, I cannot stay. The assassination, you understand? A man is being held. Jaeger, I want you to give the Doctor all the help he needs to get that thing open. Doctor, I'll keep you informed about Miss Grant, and you'll keep me informed about your progress, won't you.

[Solos]

(With the guards close behind, Ky hides Jo in a stand of buddleia.)
STUBBS: It's now two. Come on.
(Stubbs and Cotton go one way, the other guard in the opposite direction. Ky waits and then pounces on the lone guard and takes his oxymask to Jo.)

[Marshal's office]

(The Marshal enters and dismisses his guards.)
MARSHAL: Greetings, son of Varan.
VARAN JR: Why have I been brought here a prisoner? It was upon your orders that I killed the Administrator. You said he was an enemy of our people.
MARSHAL: You've done well. Now for your reward.
(The Marshal holds up the assassination device while Varan storms through the corridors.)
MARSHAL: Amusing little device, isn't it? Works perfectly.
(Varan Junior clutches his abdomen and falls dead. Varan enters and goes to his son's body. He performs a customary rite over it.)
VARAN: Achiksi. So.
MARSHAL: No regrets, Varan. First the Administrator, now an attempt to kill me. He was in league with Ky.
(Varan draws his sword.)
VARAN: You lie! You ordered us to kill the Administrator!
MARSHAL: Others will believe me!
(The Marshal fires at Varan but misses. Varan leaves and the Marshal activates his baton-comm.)
MARSHAL: Attention! Attention! This is the Marshal speaking.

[Skybase One]

MARSHAL [OC]: The Solonian Varan has gone mutant. He is at large on Skybase. If taken, he must be dealt with immediately.

[Marshal's office]

MARSHAL: Calling Solos. Calling Solos. This is the Marshal. Stubbs and Cotton, come in.

[Solos]

(Stubbs and Cotton are by their fallen comrade.)
STUBBS: But we're almost on them, sir.
MARSHAL [OC]: I want one of you up here immediately. Out.
STUBBS: Stay here.
COTTON: Thanks. Stubbsy?
STUBBS: Yeah?
COTTON: Someone's pinched his mask.
STUBBS: I'll send some medics down to pick him up.

[Skybase One laboratory]

(Jaeger has rigged up a laser looking probe device aiming at the egg.)
DOCTOR: You know, I can't think why you people ever came here.
JAEGER: Thaesium, Doctor. This planet is one of the richest fuel sources in the galaxy, or it used to be.
DOCTOR: Are the deposits now exhausted?
JAEGER: More or less.
DOCTOR: So, now you plan to colonise the planet in earnest, if you can change the atmosphere?
JAEGER: That's my problem, not yours.
DOCTOR: Well, there are other people concerned, you know?
JAEGER: Such as?
DOCTOR: Well, the Solonians, for example. After all, it is their planet.
JAEGER: Was, Doctor. It is Doctor, is it?
DOCTOR: I think you'll find that
(The Doctor changes three plugs around on the probe.)
DOCTOR: That should hold the proton beam steady, Professor.
JAEGER: I think that this whole thing is a senseless waste of time! Particle reversal. Nobody has ever achieved it.
DOCTOR: On the contrary, my dear chap, I find it a very useful research technique.
JAEGER: What do you expect to happen?
DOCTOR: I expect the particles to reverse and for the box to turn itself inside out. What's on the outside will be on the inside, and what's on the inside will be on the outside where we can see it.
JAEGER: Rubbish!
DOCTOR: You think so? Come over here and see for yourself.
(The Doctor unwinds the wires from around a control box and moves away from the device.)
DOCTOR: You ready? Then watch.
(Lights flicker over the surface of the egg and a collection of writings are briefly on the outside until the device goes bang and it all returns to normal.)

[Skybase One Herbarium]

(Varan uses his sword hilt to smash the lock and go inside. Two guards peer into the dense greenery with it's watering system.)

[Mine entrance]

(Ky puts Jo down a short way inside the tunnel, then takes her arms and gently lifts them above her head and down again onto her chest several times. She coughs, sits up and Ky removes the mask.)
JO: What is this place?
KY: A disused mine. One of many on Solos.
JO: I remember running.
KY: I nearly left you to die.
JO: What about the mask?
KY: A guard's.
JO: He'll
KY: He'll be all right if he takes it easy. You won't need this while you're in here. The daylight makes the air poisonous to Overlords. You are from Earth, but you are not
JO: The Doctor! We came to help you.
KY: Ah, the Overlord with the box.
JO: For goodness sake.
KY: I'm sorry. My people know Earth men only as Overlords. It's difficult to think otherwise.
JO: The box, it was for you. But that's why I followed you.
KY: Me? Why?
JO: I don't know.
KY: Is it weapons?
JO: I don't know!
KY: Who sent you?
JO: I. We must ask the Doctor.
KY: How?

[Skybase One laboratory]

DOCTOR: There are bound to be one or two snags to begin with.
JAEGER: But it worked?
DOCTOR: Well, of course it worked.
JAEGER: But theoretically it's impossible.
DOCTOR: I don't suppose you saw what it was, did you? Inside, I mean?
JAEGER: Not clearly, but the process
DOCTOR: Was all over in a flash. Yes, I know.
(The Marshal and Stubbs enter.)
MARSHAL: Is Varan here?
DOCTOR: Who?
MARSHAL: Jaeger, have you seen him? Varan, the Mutt.
DOCTOR: Another mutant?
MARSHAL: He was heading this way. Jaeger!
JAEGER: No, Marshal, I haven't seen him. I've got more important things to do.
MARSHAL: So long as that Mutt stays alive, he's a menace to everybody on this Skybase. He was behind the assassination plot with Ky.
DOCTOR: And now you say he's mutating?
GUARD [OC]: Mutant Varan hiding in storage section, sir.
STUBBS: They've located him, sir.
MARSHAL: All right, Stubbs, you know what to do.
STUBBS: Sir.
DOCTOR: Marshal?
MARSHAL: Mmm?
DOCTOR: I wonder, could I perhaps go on this Mutt hunt with you?
MARSHAL: Out of the question.
JAEGER: I'm sure the Doctor has good reason. He'd find it most interesting.
MARSHAL: What?
(Jaeger jerks his head to indicate 'get him out of here'.)
MARSHAL: Oh, very well. Stubbs?
STUBBS: Sir?
MARSHAL: Keep an eye on him.
STUBBS: Yes, sir. I will.
(The Doctor and Stubbs leave.)
MARSHAL: Well?
JAEGER: With that man's help, I could the whole atmosphere regeneration project operational within a week.
MARSHAL: What?
JAEGER: He understands particle reversal. He could speed up the whole process.
MARSHAL: Then we must be sure he stays with us. Yes, his assistant's the key to that as well.

[Mine]

(Ky is building a fire.)
JO: How long before they track us down?
KY: The caverns run for miles. They will never find us.
JO: But that means neither will the Doctor.
KY: We must wait. My people will tell me when the Doctor comes.
JO: Your people?
KY: The dispossessed, the outcasts, the terrorists, as the Overlords label them. Tell me about the caverns of Earth.
JO: The what?
KY: The caverns, where you live on Earth.
JO: I live in London.
KY: A sky city.
JO: No, London. London on the ground.
KY: No, I have seen pictures of Earth. No one lives on the ground. The air is too poisonous. And soon Solos will be the same. The Overlords only promise independence so they can go on plundering our resources, turning our green fields into their grey slagheaps. Am I not right? Is it not true?
JO: I don't know. It's rather a long time since I left Earth.
KY: Once my people were farmers and nomads. Now look at them. Slaves in factories and mines. Already the pollution is causing mutations. The Mutts, as the Marshal calls them. Mutts!
JO: What happens to them?
KY: They are killed. Hunted down and killed. Or if they escape they hide in places like these.
(Like the creature up the passageway.)

[Skybase One Herbarium]

DOCTOR: What is this place anyway? What's it for?
STUBBS: Seed propagation. Earth crops for Solos. Varan? Varan! It's no use, me old son. Let's get it over with.
DOCTOR: Get it over with? You don't intend shooting him in cold blood, do you?
STUBBS: It's the only way.
DOCTOR: How do you know?
(They split up.)
STUBBS: Come on, Varan. Varan? Make it easy on yourself.
(Varan pricks Stubbs with his sword, making him drop his weapon. They struggle hand to hand.)
VARAN: Varan is no Mutt, Overlord! I am a warrior and I fight like a warrior!
(The Doctor picks up Stubbs' weapon.)
DOCTOR: Varan, no! Varan! Varan, wait!
(The Doctor shoots the sword out of Varan's hand then returns the weapon to Stubbs.)
DOCTOR: Don't be a fool, Stubbs. Can't you see? There's no sign of any mutation.
STUBBS: But the Marshal said he was a mutant.
VARAN: The Marshal has murdered my son.
DOCTOR: I think you'd better tell us what you know, quickly! We're your only chance.

[Marshal's office]

COTTON: I thought you knew, sir. The guard's mask was gone when we found him.
MARSHAL: No, Cotton, I did not know. I'm surrounded by incompetents!
COTTON: Sir. Sir?
MARSHAL: Well?
COTTON: At least it means the girl is still alive.
MARSHAL: Yes, Cotton. But Ky has got her and not us. I want that girl found, understand? One more thing. As far as the Doctor is concerned, we have already got her.
COTTON: Sir?
MARSHAL: We have already got her, Cotton. She's in hospital on Solos. Right?

[Skybase One]

STUBBS: You mean His Nibs fixed up the whole thing? Had the Administrator done in and then swung the blame on the natives?
DOCTOR: That's right. You heard Varan's story.
STUBBS: I see. And if there's independence the Marshal's out of a job.
DOCTOR: Yes, exactly. But now the planet's under marshal law, his nibs, as you call him, means to keep it that way.
STUBBS: So what do we do?
DOCTOR: Keep Varan in hiding. Tell the Marshal he's been dealt with. I can't move against him openly until I am sure Miss Grant is safe. I'll just have to play for time.

[Marshal's office]

(The Doctor and Stubbs enter.)
MARSHAL: Ah, Doctor. Good news. Stubbs, did you find Varan?
STUBBS: He's been dealt with, sir.
DOCTOR: Dealt with.
MARSHAL: These Mutts are a bigger menace than you realise, Doctor. As no doubt Miss Grant will tell you.
DOCTOR: You've found her, then? When can I see her?
MARSHAL: Cotton?
COTTON: She's receiving oxygen treatment. In a day or so.
DOCTOR: A day or so?
MARSHAL: Possibly longer. She was in pretty poor shape when Cotton found her.
DOCTOR: What about Ky?
MARSHAL: Ky left her to die, Doctor. The whole planet will remain under marshal law until the fuss of the assassination dies down. Meanwhile, Doctor, Professor Jaeger could use you on a project of some urgency. It will pass the time.
DOCTOR: Until you let me see Miss Grant, you mean.
MARSHAL: Exactly. 

[Skybase One laboratory]

(Jaeger's plan is being drawn out on a wall display.)
JAEGER: What I propose to do is to bombard these layers of the atmosphere with ionisation rockets at these points. This will provide a barrier against the ultra-violet rays which create the poison mist.
DOCTOR: What you're proposing, and do correct me if I am wrong, is an all out rocket attack on a defenceless planet.
JAEGER: But these aren't military rockets.
DOCTOR: Try telling the Solonians that.
JAEGER: I can't understand your concern, Doctor. This planet, as it stands, is no longer of any use unless we make the atmosphere breathable.
DOCTOR: Even if it means wiping out every Solonian in the process?
JAEGER: Earth is fighting for its survival. The side-effects are of no importance!
DOCTOR: Genocide is a side-effect? You ought to write a paper on that, Professor.
JAEGER: Perhaps you have an alternative suggestion?
DOCTOR: Yes, perhaps.
JAEGER: Particle reversal, no doubt. Your little forte?
DOCTOR: Particle reversal is one way. Not as violent as yours, of course, but the result will be the same.
JAEGER: The question is, Doctor, can it be done?
DOCTOR: Well, we could try an experiment, couldn't we?
(Cotton enters.)
COTTON: The Marshal wants to see you, Professor.
JAEGER: Can't it wait?
COTTON: You know the Marshal.
JAEGER: Oh, very well then.
(Jaeger leaves.)
COTTON: Sir?
DOCTOR: Hmm?
COTTON: I've been chatting with Stubbs. He's a kind of mate of mine.
DOCTOR: Oh yes?
COTTON: About Varan, and about Miss Grant.
DOCTOR: When can I see her, Cotton?
COTTON: That's it, sir. You can't. We didn't find her.
DOCTOR: What?
COTTON: As far as we know, she's still with Ky.
DOCTOR: That means I've got to find both of them. How am I going to do that?
COTTON: All the guards have orders to stop you leaving this section.
DOCTOR: Is there any other way to the transfer station?
COTTON: Afraid not, sir.
DOCTOR: Cotton, is there an emergency power supply to the transfer station?
COTTON: Yes, it. Why, sir?
DOCTOR: What would happen if I blew the main power supply to the whole of Skybase?
COTTON: Sheer chaos.
DOCTOR: Yes, exactly. But if the emergency power supply to the transfer station were already switched over.
COTTON: You could slip down to Solos in the confusion.
DOCTOR: Yes, exactly. Can you get the power switched over?
COTTON: I can try.
DOCTOR: Good, now I'll tell you what I want you to do
(Jaeger enters.)
JAEGER: Cotton, who told you that the Marshal wanted to see me?
COTTON: He did, sir.
JAEGER: Then one of you must be mad.
COTTON: Oh, yes, sir. Sorry, sir. Maybe he changed his mind, sir.
(Cotton leaves.)
DOCTOR: Professor, I've been thinking. Perhaps we could try an experiment, just to prove whether I'm right or wrong about particle reversal.
JAEGER: Good.
DOCTOR: But we'll need to link up to the main power supply.

[Skybase One transfer section]

(Cotton approaches the guard, clip board in hand.)
COTTON: Orders to check stand-by equipment.
(The guard gives him access to the control panel, and Cotton presses buttons.)

[Skybase One Herbarium]

(Stubbs enters.)
STUBBS: Varan! Listen. We're going to try and get you off Skybase. Now when I go, I shall leave this door unlocked.
VARAN: How do I know this is not just another Overlord trap?
STUBBS: When the time comes, you head straight for the transfer station, but wait for the signal first.
VARAN: What signal?
STUBBS: You'll hear them announce a power failure. That'll be your chance.
VARAN: When will this signal come?
STUBBS: That's it, we don't know. You'll just have to trust us, Varan.

[Skybase One laboratory]

(The Doctor runs a large cable from the atmosphere modifier to the reversal device.)
JAEGER: Surely you'll overload the whole power supply?
DOCTOR: Oh no, not a bit of it, old chap. That modulator's utterly reliable, but I'd be very grateful if you'd keep a close eye on it, would you? Well, are you ready?
JAEGER: Yes.
DOCTOR: Here goes.
(The Doctor flicks a switch on a wall panel and the modulator lights up. A noise grows quite loud.)
DOCTOR: It's all right, don't worry. Just you keep your eye on that centre dial.
(The modulator blows up, knocking Jaeger out. The Doctor grabs the egg and leaves.)
MAN [OC]: Skybase One. Emergency! Emergency! We have power failure.

[Skybase One]

(Varan leaves the herbarium.)
MAN [OC]: Emergency! Emergency!
GUARD: Stop or I fire!
(The guard misses.)

[Skybase One transfer section]

(The Doctor enters and checks the control board. Varan grabs him round the neck.)
VARAN: Die, Overlord, die!

Episode Three

[Skybase One transfer section]

(Two armed guards run in to see Varan and the Doctor struggling inside the Overlord's transport cubicle. Then they vanish.)

[Solos Transfer station]

(The Doctor and Varan stagger out of the cubicle. The Doctor gives Varan a sharp elbow in the midriff to break free then hits him twice. Varan draws his short sword and the Doctor uses his Venusian karate paralysing grip to stop him in mid thrust.)
DOCTOR: Now, you listen to me, Varan. For the last time, I tell you I am not an Overlord. I've come to help your people but I must find Ky.
VARAN: Ky is my enemy! I will destroy him and you too, Overlord!
DOCTOR: You will take me to Ky or I will leave you here for the guards to find. Now, do you give me your word as a warrior?
(Varan nods and the Doctor releases him.)
DOCTOR: Lead the way.
(Part way down the corridor the overhead lighting changes and there is a whooshing sound.)
DOCTOR: What the blazes is that?
VARAN: Firestorms.
DOCTOR: Firestorms, is that all?
VARAN: It is the wrath of the gods.
DOCTOR: It's a simple atmospheric disturbance, Varan, and something very much to our advantage.
(They arrive at the airlock inner door.)
DOCTOR: Well, now what's the matter?
VARAN: You have no mask. When the sun rises, you will not be able to breathe the air on Solos. No Earthman can.
DOCTOR: Did I say I was an Earthman?
(They go into the airlock. Varan opens the outer door and they leave the station.)

[Mine entrance]

(Ky and Jo are watching the atmospheric display.)
JO: How long do they usually last?
KY: The firestorms? At first it was a few minutes, now it can go on all night. Each one longer than the last, terrifying my people.
JO: Surely they're used to these thunderstorms?
KY: There were no firestorms on Solos until the Marshal began his experiments.
JO: Experiments?
KY: To make our air breathable for the Overlords but not for the Solonians. It would mean the end of my people, Miss Grant.
(A bright light illuminates a mutant, with insectoid thorax and abdomen down to the ground, tiny head, short thin arms and muscular legs. Jo screams.)
JO: There, look!
KY: It's all right. It's harmless.
JO: But it's horrible!
KY: They're people. My people. Or at least they were before the Marshal's experiments.
(The mutant comes closer. It's hands are now claws and it's head has two large mandibles and staring eyes. Ky frightens it off with fire.)
JO: I thought you said they were harmless.
KY: I don't understand it. Perhaps it's the firestorm. Usually they run away. It'll be safer further back in the cave.

[Cave]

(Ky and Jo come to a green and red lit cavern, but there are mutants sheltering there too. They go down a narrow passage.)
KY: We'd better hide in here.
(Ky makes Jo shelter in a little nook.)
KY: Don't worry. I'll drive them away.
JO: Be careful, Ky.

[Skybase One laboratory]

(The fireballs pummel the hull of Skybase.)
MARSHAL: Professor Jaeger, one of the Empire's greatest scientific minds, foiled by a simple booby trap.
JAEGER: The Doctor said it was an experiment.
MARSHAL: A booby trap, Jaeger, so he could escape.
JAEGER: It was a particle reversal. I know it was.
MARSHAL: Forget particle reversal. Get those rockets ready! You'll have to go ahead on your own now.
JAEGER: Marshal, you don't realise. I am just not ready. Without particle reversal, the whole process is too dangerous. It could get completely out of hand.
MARSHAL: Jaeger, will you get this into your maundering egghead? I want the atmosphere on the planet changed and I want it changed now! Clear? (into comm.) Get me Stubbs and Cotton. I want to see them right away. I'll be in my office.

[Outside the Marshal's office]

STUBBS: This is it, then.
COTTON: Is he on to us?
STUBBS: Well, we'll soon find out.

[Marshal's office]

MARSHAL: Ah, Stubbs and Cotton. My trusty right hand men.
COTTON: Sir.
STUBBS: Sir.
MARSHAL: Not only have you failed to capture Ky and Miss Grant, you've also let the Doctor escape to Solos.
COTTON: I tried to stop him, sir. Professor Jaeger let him get out.
MARSHAL: Silence! Prepare to pay a last visit to Solos.
STUBBS: Last visit, sir?
MARSHAL: For a while, Stubbs. And there we shall kill three birds with one stone. Mutts, Varan and the Doctor.

[Solos mine entrance]

(The Doctor and Varan find Ky's camp fire still burning.)
DOCTOR: Well, somebody's been here. I wonder why they left?
VARAN: Look!
(A mutant appears, then goes off into the night.)
VARAN: You saw? Such creatures are evil. Diseased!
DOCTOR: Perhaps, but I hope the answer to their mutation is in here. (the egg) Come on. Let's find Ky. 
VARAN: Then you must find him alone, Doctor. Varan goes no further.
DOCTOR: Something's going on in there. Perhaps it's Miss Grant.
VARAN: No! No.
DOCTOR: What is it? Varan, the great warrior, afraid of the dark?
VARAN: Varan fears nothing!
DOCTOR: I'm delighted to hear it. Come on then.
(The Doctor takes a burning branch and goes down into the mine. Varan picks up another branch and follows.)

[Cave]

(Ky is not driving the mutants back as he had hoped.)
DOCTOR: This way.
(Ky is tiring. One mutant gets past him and gets to Jo in the alcove. It drives her back to the main cave.)
KY: No! Listen to me! I am Ky! You know me, my people? I come to find refuge, not to harm you!
(But the mutants press forward. Ky falls backwards over a rock, dropping his torch. The Doctor and Varan enter. The Doctor puts down the egg and runs forward.)
DOCTOR: Leave him alone! Go on, back! Get back! Get back. Leave him be!
(Varan draws his sword and goes to help.)
DOCTOR: Go on. Back! Go on! Go on!
(Meanwhile Jo is running away from her attacker down a passage to cavern lit by pulsating blue and purple light. She enters, looks around in wonder then starts to feel dizzy. Before she collapses she sees a vague silver figure. It walks towards her and we see that it is someone dressed in a radiation suit. Back in the cave, the mutants have been driven off.)
DOCTOR: So, you must be Ky. How do you do? I'm the Doctor. That's the idea. Now then, where's Miss Grant?
KY: Why are you here, Varan? Did your Overlord masters send you to hunt me?
DOCTOR: Steady, old chap. He did help to save your life, you know.
VARAN: The Marshal has betrayed me. The Overlords are my enemies too now, Ky.
KY: At last, Varan, you see the truth. Now we can work together.
VARAN: I need no help from you, Ky. Now I shall return to my people, and lead them in battle against the Overlords.
KY: So, you are the Doctor, the friend of Miss Grant?
DOCTOR: That's right. Now, where is she?
KY: I took her to a place of safety when we were attacked.
DOCTOR: Good.
KY: Why did you come here?
DOCTOR: To find her.
(The Doctor goes and picks up the egg.)
DOCTOR: And to give you this.
(Ky takes the egg, and it opens. All three men take out the stone items within it.)
VARAN: Tablets! Sketchings! These are not weapons.
KY: Varan is right. How can these help us in our struggle? Weapons are what we need.
DOCTOR: Perhaps these tablets are worth more to you than any weapons.
KY: I have seen such signs.
DOCTOR: Well, read it, man. Well, what does it say? Read it!
KY: Why, I cannot. It is the language of the old ones. No one remembers. All our culture has been destroyed by the Overlords.
DOCTOR: But you've seen this kind of writing before?
KY: Signs like these are carved in rocks all over Solos. But no one knows, no one remembers. As far as we are concerned, Doctor, they are meaningless squiggles.
DOCTOR: Yes, but they must mean something, otherwise why would I have been sent here?
VARAN: Why indeed? Come. If we stay here, they will surely attack again.
DOCTOR: No, I'm sorry, I can't go yet.
VARAN: You are fools!
DOCTOR: I can't go yet. Not without Miss Grant.
VARAN: Is this the way to fight the Overlords? To stay here and be killed by Mutts? If you will not fight, Varan will.
DOCTOR: Now, Varan, wait. Varan, wait!
(Varan leaves. Ky puts the tablets back in the egg and it closes.)
KY: He will go back to his village and he and his men, for all their valour, will be wiped out. Swords are no use against the Overlord.
DOCTOR: No. Right, Ky. Take me to Miss Grant.
KY: This way, Doctor.
DOCTOR: There must be somebody on Solos who understands the old language.
KY: There was a man called, er, Sondergaard. A man of learning from Earth. He came to study our culture.
DOCTOR: And?
KY: After a while he disappeared. Oh, it was all arranged by the Overlords.
DOCTOR: Our friend the Marshal, again?

[Marshal's office]

(The Marshal has a map of the mines.)
MARSHAL: A simple operation. Surveillance reports show they've gone to ground there. Now, Jaeger has devised some novel gas grenades. I want men stationed at every exit. We set off the grenades, flush 'em out. All of them. Ky, Doctor, Varan, Mutts, the lot.
STUBBS: What if the grenades don't flush them out, sir?
MARSHAL: Then they'll die anyway.

[Cave]

(Ky runs up to the alcove.)
DOCTOR: Well?
KY: Well, I left her here. Perhaps she became frightened, ran off in panic.
DOCTOR: Perhaps. We'd better start searching, hadn't we?

[Skybase One laboratory]

JAEGER: I've been studying the monitoring reports since the storms.
MARSHAL: I am not interested in weather reports.
JAEGER: Then you should be. The reports show a sharp rise in temperature after every one of these storms.
MARSHAL: So?
JAEGER: There is no corresponding decrease. Marshal, Solos is getting hotter and hotter. We're moving into something which none of us have ever experienced. The Solonian summer.
MARSHAL: Hmm?
JAEGER: Ever since we've been here, five hundred years, it's been spring. Now, summer. It may become too hot for any human being to live here.
MARSHAL: And it may not. That's for you to find out, Jaeger. My first priority is to wipe out the Mutts.
JAEGER: The reports also indicate a very sudden rise in the mutation rate. More Mutts than ever, Marshal, and all moving towards your target area.
MARSHAL: Good. Good then. The more the merrier.

[Solos]

(Varan waits until a guard walks past him down the mine entrance, then runs outside. The other three members of the patrol start shooting as he dodges through the scrub. The four chase him a short way then give up.)

[Cave]

(Ky and the Doctor meet back in the main cave.)
KY: No?
DOCTOR: No.
KY: But she must be here!
DOCTOR: Well, we'll just have to search them all over again, won't we?
KY: If the torches last, and they don't attack.
DOCTOR: What, you heard them?
KY: They're watching us all the time.
DOCTOR: Yes. They don't attack us in the tunnels. Only in here. This chamber must be important to them.
KY: I feel it myself.
DOCTOR: Feel what?
KY: A sensation. An awareness of being drawn here. This is a warm, safe place. A centre. A sort of instinct.
DOCTOR: Yes. Yes, it's strange. Let's keep searching. Come on.

[Mine passage]

MARSHAL: Hurry up. I want those gas grenades here. Give me those blast packs. No one else is to know about this, understood?
(The two guards leave. Stubbs and Cotton arrive and the Marshal hides the blast packs behind his back.)
MARSHAL: Everything ready?
STUBBS: Yes sir. Er, excuse me, sir?
MARSHAL: Well?
STUBBS: I think we should do something about finding the Doctor, sir.
MARSHAL: Do you now.
STUBBS: Professor Jaeger said he was important, sir.
MARSHAL: Well, Cotton?
COTTON: I agree, sir.
MARSHAL: I thought you would. Very well, Stubbs, you and Cotton. I'll give you fifteen minutes, no more.
STUBBS: Right, sir.
MARSHAL: You keep in radio contact all the way.
STUBBS: Sir.
MARSHAL: I want to hear every word. And if you come across Ky, make sure you make a better job of him than you did of Varan!

[Varan's village]

VARAN: Ho! Varan is returned!
(An old man is lying on a cot in a rough hut.)
OLD MAN: Varan.
VARAN: What has happened? Where are my people?
OLD MAN: The fire.
VARAN: Speak!
OLD MAN: The firestorms. Evil. A plague of evil. Fire from the sky.
VARAN: Listen to me. Summon my council. Go, beat the war gong!
(The old man does so, and shows us that he has started mutating.)

[Mine passage]

STUBBS: Doctor? Doctor?
COTTON: Doctor?
STUBBS: Doctor?
STUBBS [OC]: Doctor? Doctor?
KY: Overlords! We must abandon the search. They will trap us here.
STUBBS [OC]: Doctor!
COTTON [OC]: Doctor!
DOCTOR: All right. Quick, back to the chamber.
STUBBS: Let's try this way.

[Cave]

KY: If they attack now
DOCTOR: Shush! Wait. listen.
(They hear someone moan.)
DOCTOR: That's Jo Grant in there somewhere. Jo? Jo, are you in there? Jo?
(Jo is in a side chamber, lying on the ground.)
DOCTOR: Jo? Jo, are you all right? Jo?
JO: Doctor.
DOCTOR: Yes, it's all right. It's me.
(Searchlights flood the alcove.)
STUBBS: Ah, there you are.
KY: Run, Doctor!
DOCTOR: No, Ky!

[Mine passage]

STUBBS [OC]: It's us, Doctor. Stubbs and Cotton. Is Miss Grant with you?
DOCTOR [OC]: Yes, she's over here. She appears to be injured.
(The Marshal turns off his comm. and speaks to his guards.)
MARSHAL: Right, prepare the grenades.
GUARD: But, sir, they're all in there.
MARSHAL: Exactly. Fire the grenades.
(The guards throw the gas grenades further down the passage.)
MARSHAL: Pull out! Everyone out of the cave.
(The Marshal fastens the detonators to the passage wall and triggers them, setting the timer.)
MARSHAL: (into comm.) All sections, seal off exits. Fire grenades.

[Cave]

STUBBS: (into comm.) Hello? Hello? Lost contact.
(The thick, heavy gas drifts along the mine passages.)

[Varan's village]

VARAN: Why does no one come? Where are my warriors?
OLD MAN: Your warriors have fled, Varan.
VARAN: Am I left with nothing but mutants?
OLD MAN: They too. It is the way with us all, old and young, those who can walk have gone to the mines, Varan, to the mines.
VARAN: Why? Why has this curse come upon us?
(Varan sees scales forming on the back of his hand.)
VARAN: Urgh! No! No, no, no, no!
VARAN [OC]: Go, Varan. Go to the place of sleeping. The place of darkness and light. Go, Varan, go. Go. Go. Go.
VARAN: No. No, I was born to fight. Varan will not die sleeping!

[Cave]

(A group of mutants in a passageway encounter the gas, and collapse.)
JO: A passageway, full of light. Even the rocks were glowing. I remember walking towards the light.
DOCTOR: Yes?
JO: And then there was this noise in my head. I couldn't hear, I couldn't see properly. It was then I started to get dizzy.
DOCTOR: Mmm hmm.
JO: There was a figure, a silvery figure.
DOCTOR: A mutant?
JO: I don't know.
DOCTOR: Well, and then what?
JO: I'm sorry, Doctor. I fainted.
DOCTOR: Well, whatever it was, it brought you back here.
STUBBS: I'd better tell His Nibs what's going on.
DOCTOR: Here, just a minute. I don't particularly want to find myself in the Marshal's hands again, thank you very much.
COTTON: Better off on Skybase than in here. You'll have to hurry, old son. The attack's due to start any minute now.
DOCTOR: Attack?
COTTON: Gas. The Marshal's solution to what he calls the Mutt problem.
JO: Doesn't he know we're in here?
KY: He knows.
COTTON: I think we ought to move out now, before it's too late.

[Outside the mine entrance]

MARSHAL: What's the count?
GUARD: It seems to be swarming with Mutts, sir. They're attracted to the place.
MARSHAL: Mmm, they go there to die. They have the old idea of the elephant's graveyard. Right, should be any moment now.
(Bang! Bang! Smoke and debris drift out of the mine entrance. Below ground, Stubbs smells the gas, then sees it and runs back.)

[Cave]

DOCTOR: Let me see those tablets again, Ky. The answer must be here somewhere.
STUBBS: Doctor! Gas! They've started the attack already.
COTTON: We've got to get out.
STUBBS: We can't get out. The Marshal's sealed us in.
COTTON: What are we going to do?
(The gas starts to drift into the cave.)

Episode Four

[Cave]

JO: Look!
(Jo points at a silver-suited figure. It gestures for them to come towards it.)
JO: That's it. The thing I saw. No, don't shoot. Look.
(The mine rumbles.)
DOCTOR: Whatever it is, I think we'd better follow it. Come on.

[Mine passage]

(This passage is clear of gas. There are distant explosions.)
STUBBS: Making sure of it this time.
COTTON: Huh?
STUBBS: The Marshal. That's the exits.
COTTON: Was the exits.
STUBBS: Yeah.
KY: The Overlords are very thorough.
STUBBS: If it goes on like this, the whole lot'll come down.
COTTON: On top of us. Hurry up, Stubbsy!
STUBBS: All right, all right.
COTTON: Where's he talking us anyway?
(They arrive at a large metal door set in the passage wall. The suited figure opens it and steps inside. The Doctor takes something from his pocket and tests the edge of the door.)
DOCTOR: Lead. What does lead mean to you, Jo?
JO: Radiation?
DOCTOR: Yes, exactly.

[Sondergaard's laboratory]

(They go inside a room with a laboratory bench and some equipment. The suited figure closes the door and removes its helmet and gloves, revealing himself to be a cheerful bald human male with a European accent.)
SONDERGAARD: Welcome. You must not be alarmed. My name is
DOCTOR: Professor Sondergaard, I presume.

[Solos]

MARSHAL: Right, I am returning to Skybase. I want every exit sealed. Understand? Every exit.
GUARD: That's impossible, sir. These mine galleries stretch for miles. We'll be here for weeks.
MARSHAL: Mmm hmm. Give the gas a while to disperse, then take a squad down to the galleries. Who knows, you may find some survivors down there. Right, I'm returning to the Skybase. Report to me there.

[Sondergaard's laboratory]

(Sondergaard takes off the rest of the suit. He is wearing Solonian clothes underneath.)
SONDERGAARD: There is radioactivity present throughout the cave system. Oh, it's natural in a thaesium mine, and it's not dangerous, unless you're here for many years, as I am, or unless you find yourself in an unstable zone, as you did, young lady. The entrance you found led you straight to the heart of the most dangerous radioactivity.
JO: So it was you I saw, and you brought me out.
SONDERGAARD: Ha! I didn't know what to do. I couldn't let you die, so I carried you as quickly as I could out of the radioactive zone to where I hoped your friends would find you.
JO: Well, thank you, Professor.
KY: You were given up for dead years ago.
SONDERGAARD: Yes, so were many others in the mines. The mutants, for example.
JO: The mutants? Well, they attacked us and tried to kill us.
SONDERGAARD: Yes, I know. There are more now, many more, and as their numbers increase, so it seems does their aggression. Oh, it's not an isolated phenomenon. The same behaviour may be observed in rats when confined.
KY: And who did this to my people? Who hunted them down like wild animals? The Overlords!
DOCTOR: This, er, increase in aggression that you speak of. It seems to be spreading.
KY: Aggression, yes! And who were the first aggressors?
DOCTOR: Ky! This is not a political meeting. We're all on your side, you know, all of us.
KY: Him? Why does he hide in these caves? To experiment on my people!
DOCTOR: Look, give him a chance to explain!
JO: Please, Ky.
SONDERGAARD: Well, he has my sympathies. Do you think I've chosen to live here? To work with this primitive equipment? I was young, ambitious. I hoped to make many great discoveries here. And my first was that Solos had become a slave colony. I was unwise enough to try to inform Earth control. The Marshal intercepted my report. I was lucky to escape with my life. I managed to reach the caves. I've been here ever since.
DOCTOR: But you have continued with your research?
SONDERGAARD: As well as I could. As you see, I lack equipment. If it were not for the mutants, I would not have been able to survive here.
KY: My people help you?
SONDERGAARD: They did. We were all outcasts. We helped one another. Once they stole food for me, and clothing.
DOCTOR: And now?
SONDERGAARD: Now they don't come near me. It is as if I were
KY: Diseased?
SONDERGAARD: Who knows? Perhaps they're right. Strange things are happening on Solos, Doctor. Oh, not just to the people, but to the plants, the soil, the atmosphere, even the weather. The whole flora and fauna of Solos.
(The Doctor looks at specimens of plants in jars.)
DOCTOR: Professor Jaeger's experiments.
SONDERGAARD: Exactly, and my belief is this. At first the changes were natural, but now Professor Jaeger's experiments have accelerated the changes and something is seriously wrong.
DOCTOR: Yes. Yes indeed. But why was I sent here? Where do these tablets come in? Ky.
(Ky opens the egg.)

[Skybase One laboratory]

(Jaeger is working on the particle reversal device.)
MARSHAL: Are the ionisation rockets deployed?
JAEGER: Hmm?
MARSHAL: The rockets, man, for the bombardment!
JAEGER: Marshal, this is not a war.
MARSHAL: Oh?
JAEGER: This is a scientific application of ballistics. An experiment to show that population control can be affected by atmospheric means.
MARSHAL: Of course, of course, Jaeger, but let's get on with it, shall we? Experiments, population control. Jargon, Jaeger! This is war!

[Sondergaard's laboratory]

(Four stone tablets are on the lab bench.)
SONDERGAARD: Extraordinary. This wonderful, Doctor, marvellous.
DOCTOR: Yes, but what do they mean?
SONDERGAARD: This is the same kind of hieroglyphs I've seen in the old temples.
(Sondergaard fetches a paper.)
SONDERGAARD: All over Solos you see the same symbols, you see.
(It is a copy of a symbol that was on the cave wall.)
DOCTOR: Yes, I can see that, Professor, but can you read them?
SONDERGAARD: Well, I can try. I have approximate translations for many of the basic symbols. One might call this the Solonian book of Genesis. The lost tablets. This, Doctor, is the story of how Solonian civilisation began.
(There is an explosion and part of the ceiling comes down.)
DOCTOR: And ended, if we don't get a move on, I think.
STUBBS: Doctor, that wasn't a blast pack, or a grenade. That was the mountain itself. The tunnels are falling in. Now if we stay here, we're finished. All of us.
DOCTOR: Professor. Professor, is there another way out?
SONDERGAARD: Yes, yes, there is a way, but it's dangerous. It leads to a native village a few miles from here.
KY: Varan's?
SONDERGAARD: Yes, I believe so.
STUBBS: Well, let's go then!
SONDERGAARD: No, no, no, I must stay.
STUBBS: Doctor?
DOCTOR: No. Sorry, Stubbs, no, you go. Take Miss Grant with you. The Professor and I have got work to do.
JO: You're not going to stay here, Doctor?
DOCTOR: Jo. Look, the key to everything lies here in this room. These tablets, Professor Sondergaard's records. I must find the answer.
JO: Yes, I know but you heard what he said. The whole mountain is caving in.
DOCTOR: We shall have time.
JO: But, Doctor, you can't
DOCTOR: Jo, please. Please, don't argue with me. I'll join you later.
STUBBS: Come on, Miss Grant. What about Varan?
KY: I can handle him.
SONDERGAARD: To find the shaft that leads to the passageway, take always the path leading up.
(Stubbs, Ky, Jo and Cotton leave.)
SONDERGAARD: Now then, Doctor. Now, this particular symbol here, for instance, is the Solonian symbol for life.
(The four make their way up a passage. Jo stumbles and sees a mutant some way behind them.)
SONDERGAARD: Now then, this pattern repeated is almost the same, and this is the Solonian sun symbol.
DOCTOR: Yes, well, they aren't numbers, so it can't be a code. Let's try something else. Fire, earth, air, water. No, all right, that's no good.
SONDERGAARD: Well, er, a cycle, perhaps, representing some form of chemical process.
DOCTOR: Yes, but the process keeps repeating itself. What process repeats itself?
SONDERGAARD: Well, life.
DOCTOR: Life in some form will always go on.
(Another bit of ceiling falls in.)
SONDERGAARD: Let's hope so.
DOCTOR: Yes.

[Mine passage]

(Jo spots a guard down a side passage.)
JO: Look, a guard!
(Ky ducks down another side passage. Cotton grabs Jo and Stubbs runs back as the guard raises his weapon.)
STUBBS: All right, mate? It's me, Stubbs. Here, old Scottie.
(The guard shoots at Stubbs but misses. Ky comes round behind him and knocks him out.)
STUBBS: Come on. Better try this way.

[Sondergaard's laboratory]  

DOCTOR: It must be a code of some kind. It must. Eureka, it's a calendar! Spring, summer, autumn, winter.
SONDERGAARD: But Solos has no seasons. It does not tilt on its axis relative to its sun.
DOCTOR: Well, it may not tilt, Professor, but it could move closer. Look, these ellipses here, they're the orbits.
SONDERGAARD: But Solos takes two thousand years to go round its sun. We know that.
DOCTOR: Then the seasons must be five hundred years long.
SONDERGAARD: Possibly.
DOCTOR: See, these signs here. They only appear in the summer. And these little matchstick men here only appear in the spring.
SONDERGAARD: Yes, but what about these spirals? They're like small sun symbols.
DOCTOR: Yes, like small sun symbols. Well, yes, but that's it! That that's what I said. That's radiation. That's thaesium radiation! So that's why they sent me here. Professor, I want you to take me to that place where you found Jo Grant.
STUBBS: The radiation cave? But I've only one suit. If you spend any time in there without one, Doctor, you will die. Any man would.
DOCTOR: Any man, perhaps.
(More debris falls from the ceiling.)
DOCTOR: Hurry, Professor.

[Mine passage]

(The four have found another upwards passage.)
STUBBS: This is it. Look!
(A shaft leads straight to the surface.)
STUBBS: If we can reach that ledge. Right, Cotton, you first, then Ky.
JO: If only we had a rope.
(A Solonian looks down at them.)
COTTON: What? What is it?
JO: Look!
(The Solonian has disappeared.)
JO: There was someone there, I tell you. There was!
COTTON: Well, he's not there now, Miss.
JO: But he was there. He was wearing a helmet.
KY: A warrior?
JO: Could have been.
KY: If we are near Varan's village, his people are in a savage mood.
COTTON: Right.
(Cotton climbs the rough walls of the shaft.)
STUBBS: Anything?
COTTON: No, nothing!
STUBBS: Right, up you go.
KY: Varan will be somewhere near. (Ky goes next, closely followed by Jo and Stubbs.)

[Varan's village]

(Varan's face is going scaly now. He addresses three warriors.)
VARAN: My people, we are all who are left. But we are warriors yet. Shall we crawl away and die in darkness like the rest, or shall we fight, one last time?
WARRIOR [OC]: Varan!
(A solonian guard runs in.)
WARRIOR: Varan! Varan. Overlords, from the place of darkness.

[Mine passage]

DOCTOR: Where is it?
SONDERGAARD: This section here.
(The entrance is sealed by a large round, carved stone.)
DOCTOR: Right, there it is. How do we move it? 
SONDERGAARD: That way.
DOCTOR: This way. Right? 
SONDERGAARD: Yes.
(They roll the stone away from the opening and pulsing light floods out. Sondergaard seems hypnotised by the rhythm.)
DOCTOR: Your helmet, Professor. Your helmet, man!
SONDERGAARD: Oh, yes. What about you, Doctor? The intensity in there is far greater.
DOCTOR: Don't worry about me. I've already prepared myself. Ready? Come on.

[Radiation cavern]

(Their movements are slightly slower than normal as they walk through the ever shifting light patterns.)
DOCTOR: It's magnificent. It's like a cathedral.

[Varan's village]

(Cotton is sharing his oxymask with Jo. The village seems empty and the fire has gone out underneath the cauldron. A warrior rushes in, sword raised and shouting.)
KY: No! Don't shoot!
(Varan grabs Jo from behind.)
VARAN: Your weapons, Overlords.

[Radiation cavern]

(Even inside his protective suit, Sondergaard is suffering the effects of the lights.)
DOCTOR: Come on, we've got to get to the heart of it.
(The Doctor half carries Sondergaard a little further.)
SONDERGAARD: No. No, I can't. You, you go. Leave me.
(Sondergaard falls to the ground. Shielding his eyes with his hands, the Doctor reluctantly goes on towards a bright, shining figure. He takes a large carved gemstone from it then makes his way back to Sondergaard. He helps the man up then hoists him over his shoulders in a fireman's lift and carries him out of the cavern.)

[Varan's village]

(The four are now tied up.)
VARAN: Overlords, you will suffer as I have suffered. And you, renegade, will die.
KY: You are a fool, Varan. Attack Skybase and you will sacrifice your men for nothing.
VARAN: What have we to fear? We have nothing left now but revenge.
KY: You cannot hope to get into Skybase, much less destroy it.
VARAN: You forget. We have the Overlords, we have their weapons. You and the woman will act as shields. So you see, renegade, you will die for a cause. The cause of Varan's revenge. Now, move!
WARRIOR: Move!

[Marshal's office]

(Jaeger is escorted in.)
MARSHAL: Well? Has the countdown started?
JAEGER: Started? Marshal, are you aware how long it takes to check out an orbital rocket?
MARSHAL: You have the engineers, haven't you?
JAEGER: They've deteriorated almost as much as the hardware.
MARSHAL: Huh! Excuses, Jaeger, excuses!
(The comm. trills.)
MARSHAL: Yes?
MAN [OC]: Message from deep space.
MARSHAL: What?
MAN [OC]: Message reads. Unscheduled Hyperion space shuttle now on course Solos. ETA twenty two twenty twenty nine Solos time. Earth Council investigator on board.
MARSHAL: Investigator? What investigator?
MAN [OC]: Message ends.
MARSHAL: Blast the Earth council. Who do they think they are? Investigator? Investigating what?
JAEGER: Your activities should give him plenty of scope.
MARSHAL: Jaeger, if I didn't need you. Now, listen to me. When this investigator arrives, he will be met with a fait accompli. Your experiments will have been carried out, the Mutts will have been eliminated and the air on Solos will be breathable. Understand?
JAEGER: But the rockets are only half ready.
MARSHAL: Either they go or you go, Professor Jaeger. I intend to meet this investigator on the planet's surface itself, face to face, without masks.

[Solos transfer station]

(Stubbs and Cotton enter.)
GUARD: Hello, you two. Where are you going, up top? 
STUBBS: Yeah. His Nibs wants to see us.
(Varan comes up behind the guard and knocks him out with his claw. The warriors hustle Ky and Jo in.)
VARAN: You did well, Overlords. Now the way to Skybase lies open.
STUBBS: You don't stand a chance, Varan.
VARAN: We're prepared to die.
JO: What good will that do? Believe me, the Doctor will help you find a cure.
VARAN: There is no cure for this!

[Sondergaard's laboratory]

DOCTOR: Yes, of course. The Solonians are meant to mutate. The mutation is part of it. A part of an evolution. They're meant to change as their environment changes every five hundred years. A life cycle unique in the history of the universe. And now, thanks to the Marshal, threatened with extinction.
SONDERGAARD: So it's not a sickness.
DOCTOR: No, it's a metamorphosis, an adaptive change. The mutants, as we know them, are an intermediate form.
SONDERGAARD: And we've yet to see the final metamorphosis?
DOCTOR: Exactly. The radiation cave is the key to that.
SONDERGAARD: The tablets led us to the crystal. 
DOCTOR: Yes. It must play a vital part in the process, but what?
SONDERGAARD: Maybe that the cellular change is only affected by the particular radiation in the crystal.
DOCTOR: That's the extraordinary thing about it. It shows absolutely no radioactivity at all. Here, try it for yourself.
SONDERGAARD: That's impossible.
(Sondergaard runs a Geiger detector over the crystal.)
DOCTOR: Apparently not. If only we could analyse it and find out its true function.
SONDERGAARD: The equipment here's too primitive for crystallography. There's only one place.
DOCTOR: Skybase. Jaeger's lab.

[Solos transfer station]

MAN [OC]: All Skybase personnel. All Skybase personnel. Return to Skybase immediately. Repeat, return immediately. Countdown proceeding on rocket launch.

[Skybase One transfer section]

(Jo and Stubbs are already there. Warriors appear in the two booths with Ky and Cotton.)
MAN [OC]: Launch now in final stage.
VARAN: Now, Overlords, this way.
MAN [OC]: All vectors cleared. All systems green and go on countdown. Sixty seconds and counting.

[Skybase One]

MAN [OC]: Fifty five and counting.
(Stubbs and Cotton lead the way.)
MAN [OC]: Fifty one. Fifty and counting.

[Skybase One laboratory]

MAN [OC]: Forty seven. Forty five and counting.
JAEGER: This is stupid. I take no responsibility.
MARSHAL: That is for me to decide.
MAN [OC]: Forty one. Emergency! Emergency! Unauthorised personnel in transfer section! Hold countdown!
MARSHAL: (into comm.) No. Keep the countdown going.
MAN [OC]: Countdown proceeding.
MARSHAL: Guards to transfer section immediate! Nothing is to stop this countdown. Nothing! Guards!

[Mine passage]

SONDERGAARD: There. There!
(A shaft of light falls into the passageway ahead. Sondergaard collapses.)

[Skybase One]

(The Marshal is leading guards through the corridors.)
MAN [OC]: Thirty eight, thirty seven, thirty six, thirty five, thirty-four, thirty-three, thirty two, thirty one and counting. Thirty, twenty nine
JO: What are they counting?
MAN [OC]: Twenty eight
STUBBS: It must be one of Jaeger's experiments.
COTTON: You hope.
MAN [OC]: Twenty seven
VARAN: Silence!
MAN [OC]: Twenty five, twenty four
KY: This is madness, Varan.
MAN [OC]: Twenty-three
(They are now outside Bac Decon.)
STUBBS: Quiet!
MAN [OC]: Twenty two, twenty one, twenty seconds and counting.
STUBBS: In there, quick!
MAN [OC]: Eighteen, seventeen
(The Marshal's guards open fire as the group struggle to get through the door. Varan's warriors are shot.)

[Decontamination room]

(Varan is in first, followed by Jo and Cotton, Ky, Stubbs then the Marshal with his weapon raised. Varan draws his sword and the Marshal fires.)
MAN [OC]: Ten, nine, eight, seven six, five
(The Marshal's reckless fire blasts away the wall behind Varan and the Solonian is sucked out into space. Skybase tilts, everyone falls over. Cotton hangs a hand rail.)
MAN [OC]: Four, three two, one, zero!
(The rockets launch as Varan screams silently in space. The Marshal just manages to top himself being sucked out as well. Cotton is hanging on to Ky, who has Stubbs holding his leg with one arm and Jo with the other.)
MAN [OC]: Emergency! Emergency! Hull fracture in section three. Depressurise and isolate!

Episode Five

[Solos]

(The Doctor and Sondergaard walk out of a large tunnel opening and head off down a track. Suddenly there is an explosion and they dive into the scrub for cover. There are more explosions nearby.)
SONDERGAARD: What is it? What's happening?
DOCTOR: It's rockets! That fool Jaeger's bombarding the planet with rockets. It seems to have died down for the moment. Let's get out of here and find Miss Grant and the others.

[Decontamination room]

(Everyone is still hanging on for their lives.)
MAN [OC]: Sector three isolated. We are about to depressurise.
COTTON: Pressure will ease in a minute! We've got to get out before the air goes.)
(The Marshal gets out. Stubbs helps Jo and Cotton helps Ky into the corridor.)

[Skybase One]

STUBBS: Get the door.
(Cotton closes the door then the two guards untie Jo and Ky's hands.)
STUBBS: Are you all right, Miss?
JO: Yes, I think I'm okay.
MARSHAL: Very touching. Guards! Bring them!

[Solos]

(The Doctor uses a small telescope to look at Varan's village below them.)
DOCTOR: No, there's no sign of them.
SONDERGAARD: Or of Varan?
DOCTOR: No. Well, he said he was going to attack Skybase. If he ran into any of the others. Come on. Let's make for the transfer station.

[Marshal's office]

(Cotton, Stubbs, Ky and Jo are handcuffed to the rail by the upper level of the office.)
MARSHAL: This time, as you see, we are taking no chances.
GUARD: Squad ready, sir.
MARSHAL: Good. Cotton, treason. Stubbs, treason. Ky, conspiracy, sabotage, terrorism. Miss Grant, such a pity.
KY: Miss Grant had nothing to do with it!
MARSHAL: Guard! Call the squad in.
GUARD: Squad, forward!
KY: Once again, the justice of the Overlords.
MARSHAL: Exactly.
KY: You will never win, Marshal. You will never take over this planet. As long as one of my people remains alive, you will never be safe. My death is unimportant. It will only help our fight for freedom. There will be others after me.
MARSHAL: Always the speechmaker, Ky, but you're wrong. There will be no one after you. We are making sure of that. Ready. Aim.
(Jaeger bursts in and pushes aside the firing squad's weapons.)
JAEGER: No good! The whole operation ruined, Marshal, thanks to you!
MARSHAL: Later, Jaeger. I am busy!
JAEGER: I see! So tell them to get out! This is far more important!
MARSHAL: Jaeger, I am warning you.
JAEGER: Marshal, do you want to know what's happened to Solos or are you too busy playing soldiers?
MARSHAL: Guards, wait outside. You'll forgive a short postponement, I trust?
JAEGER: Here are the figures. Total failure! Every one of those rockets malfunctioned in one way or another. If they had been properly checked out as I insisted, Marshal.
MARSHAL: Jaeger, what happened?
JAEGER: I'll tell you what happened. None of the ionisation rockets exploded in the atmosphere. Every single one hit the surface!
MARSHAL: So?
JAEGER: So? Instead of seeding the atmosphere with ionisation crystals, the planet's surface itself has been contaminated. You've made yourself master of a desert, Marshal. A lethal desert. No one will be able to set foot on Solos for centuries now, once the crystals have taken effect. No one! Not you and certainly not the Investigator!
MARSHAL: Jaeger, will you shut up!
JAEGER: As for this display of megalomania, how do you hope to conceal it from the Investigator? They are not all of them as loyal as those guards. Someone will talk, if only to save his own skin.
MARSHAL: Someone like you, Jaeger?
JO: Jaeger's right, you know? Someone will talk.
MARSHAL: And I dispose of you all first?
STUBBS: You can't silence the whole of Skybase. You've got a problem, Marshal. None of the men want to stay here.
MARSHAL: My men do as I tell them.
STUBBS: That's not true, Marshal. Cotton and I aren't the only ones, you know.
JO: The Investigator's going to find out everything. The Administrator assassinated, native leaders dead or missing and a contaminated planet. Now that's not a very successful record, is it, Marshal?
MARSHAL: Very good, Miss Grant. Very convincing. You forget one thing. The Investigator still has to get here, and his ship is no match for Skybase.
STUBBS: Agreed, you could dispose of the Investigator too. But how reliable are your rockets, Professor? As for the advance warning system, the Doctor and Miss Grant landed, Marshal, landed without being detected. And the Doctor's still free.
MARSHAL: Doctor! Always the Doctor!
JO: But no one else can help you, or Solos for that matter. Do you think we didn't know about the Investigator? Well, why do you think we were sent? He's coming to confirm the Doctor's findings.
MARSHAL: Where is your precious Doctor now?
KY: He's on Solos, Marshal, with Sondergaard. And both of them are very much alive.

[Solos]

(The Doctor snaps a piece of dead shrubbery.)
SONDERGAARD: What's happening here?
DOCTOR: It's started already. Contamination from the ionisation crystals. We've got to get out of here, Sondergaard.
SONDERGAARD: It's no good. I can't. You'll have to leave me.
DOCTOR: My dear chap, I wouldn't hear of it.
SONDERGAARD: You've got to get to that laboratory on Skybase, Doctor. You stand a better chance on your own. I'll be all right. I'll rest here for a while and then go back to the caves. I'll be safe there. Now go, please.
DOCTOR: Yes, all right. You take care, all right?
(Nearby, a guard picks up something on his motion detector, and reports to the Marshal.)

[Marshal's office]

MARSHAL: You're right, Miss Grant. Your friend the Doctor, is alive, and on Solos. And we know where he is.
JO: Then why don't you arrest him?
MARSHAL: Oh, we shall, never fear.
JAEGER: You see, Miss Grant, there's a technique known as particle reversal. We wish to use the Doctor's knowledge of this technique to, as it were, sweep the dust under the carpet before the Investigator arrives.
JO: And supposing the Doctor refuses to cooperate?
MARSHAL: Oh, he will cooperate. He will, Miss Grant. You are our guarantee. Now I shall return to Solos, supervise his capture. Guard!

[Solos]

(The Marshal issues orders to four guards.)
MARSHAL: Drive him this way! Remember, keep the pressure on! I want the Doctor here, in one piece. Right, get on with it!
(The four guards chase the Doctor directly to the other one with the motion detector, who is surprised. The Doctor throws him on his back.)
DOCTOR: Goodbye!
(And runs off into the mist. The four guards arrive)
GUARD: He's heading for the transfer station. After him! Come on, move it!

[Solos transfer station]

(The Doctor locks the outer airlock door and gets into the Overlord's transfer cubicle. The guards enter and fire their weapons. They miss, the Doctor waves goodbye and vanishes. He arrives on Skybase and runs off down the corridor as two guards use both cubicles to 'beam up'.)

[Marshal's office]

(The Doctor conceals himself from his pursuers, then enters.)
DOCTOR: Cotton.
STUBBS: Doctor!
JO: Doctor!
DOCTOR: Hello, Jo. Now then, we'll soon get you out of this.
(The Doctor starts to use his sonic screwdriver on Jo's handcuffs.)
MARSHAL: Use the key, Doctor. But before you do, consider what might happen to Miss Grant.
GUARD: And the other thing.
(The Doctor hands over his sonic screwdriver.)
DOCTOR: Well, what do you want?
MARSHAL: As you're no doubt aware, Jaeger's made a complete hash of my plan to make the planet habitable. He seemed to think you could help him put it right.
DOCTOR: And if I do?
MARSHAL: Then you will live. Both of you.
DOCTOR: And if not?
MARSHAL: Oh, come now, Doctor, surely you can guess.
DOCTOR: Yes, only too easily.
MARSHAL: Then why the delay? It's not just their lives. The whole planet is at stake.
DOCTOR: Very well then.
MARSHAL: Oh, one more thing. Your superior will be arriving shortly.
DOCTOR: Superior?
MARSHAL: Yes, Earth Control has seen fit to have my project investigated. I want my reforms to have their approval. You and your friends here will confirm the necessity of stern measures. Outbreaks of plague and rebellion must be controlled, don't you agree?
DOCTOR: Marshal, you are quite mad.
MARSHAL: Only if I lose.

[Skybase One laboratory]

(The Doctor is escorted in.)
JAEGER: Ah, here you are.
DOCTOR: Well, I gather that you've made a complete hash of things.
JAEGER: This is the situation, As far as we can tell, the centres of crystal contamination have already started to spread, and in some cases link up.
DOCTOR: Mmm hmm.
JAEGER: All the living organisms seem to be affected.
DOCTOR: Well, whatever we do, we're bound to leave a few bald patches.
JAEGER: It wasn't my decision, Doctor.
DOCTOR: Oh, no. No, no, of course not. You were simply obeying orders. That's a common excuse, Professor. Right, now I'll need a macrovisor. The strongest one you've got.
JAEGER: Well, there's only one.
DOCTOR: The one you use in the transfer system?
JAEGER: Yes, but you can't use that.
DOCTOR: Well, we've got to use it. We'll have to train it on each affected area in turn, like a searchlight.
JAEGER: I thought you were going to use the particle reversal?
DOCTOR: I am, Jaeger, I am. But we shall need the beam to transfer the effect from this laboratory to the contaminated areas.
JAEGER: Oh, I see. Er, why?
DOCTOR: Well, we can hardly set it up on the surface of the planet now, can we? You've seen to that.
JAEGER: I shall have to get the Marshal's authority.
DOCTOR: The Marshal's?
JAEGER: It's not going to be easy. It means isolating Skybase.
DOCTOR: Look, for heaven's sake, stop dilly-dallying and let's get on with it. These unstable reactions are dangerous. I shall need some equipment. If we don't come up with an effective control system, we'll particle reverse Skybase and we'll be in a bigger mess than we were before.

[Marshal's office]

(The man left to guard the four prisoners gets tired, puts his weapon on the glass table and sits down with his back to them.)
KY: (sotto) Right.
(Jo collapses.)
STUBBS: Guard!
JO: Oh.
STUBBS: The girl's collapsed.
JO: Help me.
STUBBS: Well, come on, man! Get over here quickly.
JO: Please, help me.
STUBBS: Hurry up!
(The guard picks up his weapon, goes over to Jo and bends down. She snatches his weapon from him.)
JO: Right. Keys. And the other thing. (The guard hands over the handcuff keys and the sonic screwdriver.)
JO: Thank you.
(Jo frees Ky, who takes the weapon while she frees Stubbs and Cotton.)
COTTON: Well? Now what?
JO: Well, now we've got to get onto somebody of authority and tell them what's happening here.
STUBBS: That's it, Miss. Contact the Investigator.
COTTON: We can use the Marshal's communicator.
STUBBS: There it is. Right, you do that, I'll block the door.
(Cotton activates the baton-comm.)
COTTON: This is Skybase One calling Hyperion. Skybase One calling Hyperion. Come in Hyperion. This is urgent. Repeat, urgent!
STUBBS: Hurry up, Cotton. I won't be able to hold them once they get in.
COTTON: Skybase One! Skybase One! Come in Hyperion! Skybase One calling Hyperion!
(Ky cuffs the guard to the railing as three other guards blast open the door. He has given the weapon to Stubbs.)
STUBBS: Stay where you are, lads. I don't want to shoot unless I have to. Go on, get back!
COTTON: Come in Hyperion! This is urgent! Skybase One on open channel!

[Outside the Marshal's office]

MARSHAL: What's going on here? Get him! Get him!
STUBBS [OC]: Get back, Marshal!
MARSHAL: Give me that, will you?
(The Marshal takes a weapon and fires it into the office.)

[Marshal's office]

(The Marshal misses everyone.)
COTTON: Skybase calling Hyperion! Skybase calling Hyperion!
(Stubbs is no better a shot, though.)
HYPERION [OC]: Go ahead, Skybase One. This is Hyperion.
COTTON: Stubbsy, we've got 'em!
STUBBS: Well, get on with it then!
COTTON: What do I say?
JO: Here, let me. Situation on Solos critical. Marshal's attempts to convert atmosphere is causing severe loss of life. The Administrator assassinated on Marshal's orders. Marshal attempting to maintain complete control of entire planet. He must be replaced immediately! Over.
HYPERION [OC]: Message received, Skybase One. Request identification. Official information soonest. Hyperion out.
(Stubbs gets shot.)
COTTON: Stubbsy!
STUBBS: Did you get through?
COTTON: Yes.
STUBBS: Good lad, Cotton. Good
COTTON: Come on, Stubbsy. Stubbsy, man?
(Ky takes the weapon and covers the doorway.)
KY: Quick, get out. I'll follow.
JO: But what about him?
COTTON: No need to worry about him. We'd better make for the transfer section. Come on.
JO: We can't!
COTTON: Not that way! Follow me!
(Cotton takes them through a door labelled No Unauthorised Entry.)
MARSHAL: After them! Fool!

[Skybase One laboratory]

DOCTOR: What's that?
JAEGER: Ready to isolate transfer macrovisor.
(Gunfire is heard outside.)
DOCTOR: Huh? Oh, right. Carry on.
(The Doctor goes to the main door.)
GUARD: No.
(More weapons fire can be heard outside.)

[Skybase One transfer section]

(Cotton pulls Jo along ahead of Ky and the chasing Marshal. Cotton pushes Jo and Ky into the transfer cubicle.)

[Skybase One Laboratory]

JAEGER: Transfer system isolating now.

[Skybase One transfer section]

(Cotton tries to get the cubicle to work. The Marshal and his guards arrive. One of them kicks the weapon out of Ky's hands.)
MARSHAL: Guards!
(Two guards hold Cotton while the Marshal keeps Ky and Jo covered with his weapon.)
MARSHAL: Your friend the Doctor again, I'm afraid, Miss Grant. He's cut off the power, no doubt. Take these two to the radiation chamber.
(Ky and Cotton are taken away.)
MARSHAL: Now, Miss Grant, perhaps you'd be good enough to come with me.

[Skybase One Laboratory]

DOCTOR: You do realise, Professor, that the slightest accident in this stage of the proceedings.
(Jaeger nearly drops a long glass rod as he hands it down to the Doctor.)
DOCTOR: Tut, tut, tut. The slightest accident in this stage of the proceedings and we'd all reverse instantly into antimatter. Blasted out to the other side of the universe, as a flash of electromagnetic radiation. We'll all become unpeople, undoing unthings untogether. Fascinating.
(The rod is all the way in the weather control device.)
DOCTOR: Got it. Right, all we've got to do is switch on now and see what happens. Or unhappens as the case may be. All right, lower away, will you?
(Jaeger turns a dial and the top of the weather control device is lowered into place.)
DOCTOR: By the way, I didn't tell you, did I, Professor Sondergaard and I think we've discovered the secret behind the mutations. It's not a disease at all.

[Mine passage]

(Sondergaard has made it back into the mines, and lies down on a pile of spoil. A guard finds him and is about to fire when a mutant comes up behind and knocks him out.)
SONDERGAARD: Listen. Wait a minute. Listen. Can you understand me? Can you?
(A group of mutants gather round.)
SONDERGAARD: You saved me from the guard. Do you know who I am? You know me? I help you. Sondergaard. I help all the mutants, you remember?
(They nod.)
SONDERGAARD: Good, now listen. How many are there left after the rockets? How many mutants?
MUTT: Sick. Sick.
SONDERGAARD: No, no, not sick. We know now. You are supposed to become like this. You are supposed to change. Now listen to me, please. But the Overlord's experiments with the air of Solos have made the mutation rate, made the change happen wrongly. Do you follow me? The change can be put right. We know that now. The mutation rate can be made to go as it was meant to. But you must help me. You must help me find the Doctor. Will you come with me and find him? To save your people?

[Skybase One Laboratory]

(Jaeger operates the machine while the Doctor monitors readings on a console.)
DOCTOR: Now let it build up, Professor. More. More.
JAEGER: You have full power now.
DOCTOR: Right. Now here goes. Activation beginning.
(A beam flickers down from Skybase to the planet surface, then changes to another location.)
DOCTOR: What's the reading?
JAEGER: Planet surface no longer contaminated.
DOCTOR: The nitrogen isotope level?
JAEGER: Exactly as it was before my rockets landed.
DOCTOR: Good, then that's how it stays.
MARSHAL: Not so, Doctor. You'll continue to operate this device for me until Solos has an atmosphere breathable by humans, and only by humans.
DOCTOR: No!
MARSHAL: Very well. Bring in Miss Grant.
(Jo is brought in, and a guard puts his weapon to her head.)
MARSHAL: Well, Doctor.
HYPERION [OC]: Attention Skybase. Attention Skybase. This is Earth Investigator space shuttle Hyperion. We are about to dock. I repeat, we are about to dock.
DOCTOR: Well, Marshal, it seems as if your superiors have arrived. What are you going to do now?
MARSHAL: Get her out of here. Take put her with the others.
(Jo is taken away.)
MARSHAL: And now, Doctor, shall we welcome the Investigator together?
(The tiny Hyperion docks with an airlock on the end of a tunnel extending from the huge Skybase.)

[Radiation chamber]

(Jo is pushed through a round doorway over a metre up the wall of the chamber.)
COTTON: Are you all right?
JO: Well, yes, I think so.
COTTON: What's happening?
JO: The Investigator's arrived.
KY: And the Marshal?
JO: Well, from what I could gather, he's taken the Doctor to meet the Investigator.
KY: Then at last my people can expect justice.
COTTON: Doubt it.
KY: Why not? The Doctor will tell him everything.
JO: Well, why do you think we've been shoved down here? We're hostages, Ky, to make sure the Doctor says the right thing.
COTTON: Come on. Let us stay away from that wall.
(That wall has a circular recess, and it has a swirly pattern on it.)
JO: Well, why? What's wrong?
COTTON: We're in the refuelling lock, next to where we store the radioactive thaesium. That's what makes the walls glow.
JO: Thaesium?
COTTON: Nuclear fuel, Miss. We use it to power Skybase, spaceships, practically everything.
KY: How dangerous is it, this radiation?
COTTON: Safe enough for short time. Stay here too long though and, well, it builds up.
JO: How long's the Marshal going to keep us down here?
COTTON: Who knows? Don't suppose he's worried. Wait a minute. Refuelling.
JO: What is it?
COTTON: The shuttle!
KY: What do you mean?
COTTON: They'll need to refuel Hyperion, the Investigator's shuttle. They should be putting a probe out any minute now. Then live thaesium will start flooding through there. We'll all be done for!

Episode Six

[Marshal's office]

MARSHAL: How much longer am I supposed to run Skybase with my entire crew suspended from duty? I refuse to be treated like a, like a
DOCTOR: Criminal?
MARSHAL: I am warning you, Doctor.
(Guards in white and gold with ECS on their helmets enter, then three men in long gowns and gold 'wigs'.)
INVESTIGATOR: My apologies, Marshal. And who is this?
MARSHAL: This is the Doctor, as I am sure you know.
INVESTIGATOR: Your scientific advisor?
MARSHAL: Well, surely you know one another?
INVESTIGATOR: Should we?
DOCTOR: Perhaps I can explain.
INVESTIGATOR: Perhaps you can in due course. I've read your report, Marshal, and I should like to begin this enquiry, if I may, by discussing certain matters arising from it. You have been accused of some very serious crimes, Marshal. Well?
MARSHAL: Well, Investigator, I'm sure you're aware that all Colony Commanders are faced with accusations of this kind.
INVESTIGATOR: Some, Marshal. Occasionally, the accusations are justified. That is why I'm here.
MARSHAL: Of course, of course. Of course you are. You see, Solos has been beset in recent months with problems. I mean, an upsurge of nationalism, outbreak of plague, constant and growing attacks and sabotage, culminating in the assassination of the Administrator by terrorists on the eve of independence. It was at this point that I decided to impose martial law.
INVESTIGATOR: I see. How severe was this martial law?
MARSHAL: Oh, rounding up of political suspects.
INVESTIGATOR: There's no report here of any trial being held.
MARSHAL: Oh, the prisoners were allowed to escape.
INVESTIGATOR: By, er, Stubbs and Cotton.
MARSHAL: Er, yes.
INVESTIGATOR: Now deceased?
MARSHAL: Yes.
INVESTIGATOR: I see. Continue.
MARSHAL: I then took personal control of the operation and tracked these terrorists to their hideout in a disused mine area.
INVESTIGATOR: These would be thaesium mines?
MARSHAL: Correct, correct. I ordered the area to be cordoned off and the exits blown up.
INVESTIGATOR: And the natives inside?
MARSHAL: Oh, they were Mutts.
INVESTIGATOR: Mutts?
DOCTOR: He means they were all plague victims. They use the caves as a refuge.
MARSHAL: Yes, the terrorists took advantage of their unfortunate compatriots. I had no alternative.
INVESTIGATOR: And presumably thousands died as a result of your actions?
MARSHAL: Unfortunately, but their condition was incurable. I couldn't allow this risk of the plague spreading.
INVESTIGATOR: Mutts you say? 
DOCTOR: Yes. Mutant natives, sir. It's a local term. Medically speaking, accelerated genetic metamorphosis.
INVESTIGATOR: I see. You are a Doctor, I take it?
DOCTOR: I am, yes.
INVESTIGATOR: Qualified in?
DOCTOR: Practically everything.
INVESTIGATOR: Ah. Well, Doctor, do you agree with the Marshal's diagnosis that the condition of these Mutts was incurable?
DOCTOR: Yes, sir. Yes, I would.

[Radiation chamber]

(Hyperion extends its refueling rig. Ky is sweating and shaking.)
JO: Look, the walls.
COTTON: Not long now. Now sure you've got it straight, Miss? Any minute now, Hyperion's fuel probe will come through there. That's how we get out. Okay?
JO: Okay. If we don't get out soon, it'll be too late.
COTTON: Stand back!
(The refuel nozzle comes through the circular recess and opens. It is easily a metre across.)
COTTON: This is it then. Get inside, Miss.
JO: Inside?
COTTON: Fast as you can. Move! Come here!
JO: Ky!
(Jo, Ky and Cotton get into the hose just before another nozzle comes out of the other wall, where the fuel is stored.)

[Marshal's office]

(The Investigator consults quietly with his two deputies.)
INVESTIGATOR: Understand?
(Jaeger enters and goes to speak quietly to the Marshal at his desk.)
JAEGER: Do you realise Hyperion's started refuelling?
MARSHAL: Well?
JAEGER: Your prisoners are in the fuel lock. If they caught in the thaesium stream.
MARSHAL: Then they'll be totally destroyed. Convenient, isn't it?
INVESTIGATOR: Professor Jaeger, the committee will hear you now.

[Hyperion fuel chamber]

(Jo, Ky and Cotton come out of the refueling rig.)
COTTON: Up there. Quick!
JO: All right.
(They go up a metal staircase just as the chamber becomes too bright to see.)

[Skybase One airlock]

(Jo, Ky and Cotton pass back into Skybase.)
COTTON: Right.
JO: Where are all the guards?
COTTON: Worry about that later. Come on.

[Marshal's office]

INVESTIGATOR: Nevertheless, Professor, you were involved in experiments to change this planet's natural atmosphere?
JAEGER: In the laboratory, yes.
INVESTIGATOR: The accusation is that you mounted a massive operation to convert the atmosphere to one breathable by humans, but not by the native population.
JAEGER: Nonsense.
INVESTIGATOR: And further, that these experiments were the root cause of the outbreak of mutation. Well?
JAEGER: I'm a scientist.
(The Doctor coughs.)
JAEGER: And I rest my case on scientific proof only. Your scientists have made their own tests. The atmosphere of Solos is exactly as it always was. As for the Mutts, er, as for the mutants, I regret that so far we have found no solution to the problem.
INVESTIGATOR: Thank you, Professor, that will be all.
(The Investigator confers with his deputies.)
INVESTIGATOR: Well, gentleman, we have heard the evidence. In the absence of evidence to the contrary I have no alternative but to exonerate you from blame
(There is a commotion outside.)
JO [OC]: Let me pass.
INVESTIGATOR: And to declare this preliminary hearing closed.
(Jo wriggles out of the grasp of the guards and runs up to the Doctor.)
MARSHAL: Stop them! Stop them!
INVESTIGATOR: What is going on here? Who are these people?
(Ky and Cotton are brought in by the Investigator's guards.)
DOCTOR: Investigator, these are the missing witnesses. Jo, Miss Grant here, is my assistant, kept hostage
MARSHAL: Lies, all lies!
DOCTOR: Kept hostage to ensure my cooperation in this travesty of justice. Investigator, I accuse that man and that man of the most brutal and callous series of crimes against a defenceless people it's ever been my misfortune to encounter.

[Solos transfer station]

(Sondergaard checks out the area then beckons the mutants to follow him.)
SONDERGAARD: Come on. Come on. You see? There is nothing to fear. Look, I cannot help until I find the Doctor. Oh, very well, I shall go alone, and you will stay as you are now forever.
(Sondergaard gets into a transfer cubicle.)

[Marshal's office]

DOCTOR: You destroyed these poor people for no reason at all.
MARSHAL: They would have died anyway.
DOCTOR: Not died, Marshal, changed.
MARSHAL: It was my duty! My duty to save Solos from contamination!
DOCTOR: Duty? Your idea of duty was to keep this planet for yourself.
MARSHAL: They're mutants! Mutts! They're diseased! To be wiped off the face of the planet! I
DOCTOR: Need I say more, Investigator?
(The Investigator confers with his deputies, and the Doctor whispers with Jo.)
INVESTIGATOR: Can you prove your assertion, Doctor? Perhaps we could see these tablets you mention.
DOCTOR: Yes, yes, of course.
INVESTIGATOR: Well?
DOCTOR: Er, no, I'm sorry, sir, I forgot. The tablets are in the care of Professor Sondergaard.
INVESTIGATOR: Ah yes, you mentioned him in your report. Where is Professor Sondergaard now?
DOCTOR: I'm not sure, sir. Somewhere on the surface of Solos, I believe.
INVESTIGATOR: I see. And your other proofs the mutations are not harmful?
DOCTOR: Well, I can only reassure you that
MARSHAL: He can prove nothing!
DOCTOR: As I say, I can assure you, sir, that conclusive evidence does exist.
MARSHAL: Where? Where is your proof?
DOCTOR: This present mutation is one of a series of adaptive changes, sir. Solos is moving out of spring into summer, and that is why the Solonians are changing.
(Sondergaard is brought in by one of the Investigator's guards.)
INVESTIGATOR: What is the meaning of this interruption? Who is this man?
DOCTOR: This, sir, this is Professor Sondergaard, who's worked and lived on Solos for many years. He can tell you better than I what the Marshal has been doing there.
SONDERGAARD: Doctor, I don't understand. What's happening here?
DOCTOR: Don't worry, Professor. We're holding a much needed investigation. Thank heavens you've arrived just in time to tell the Investigator of our discoveries.
SONDERGAARD: Oh, yes, of course. Well, I'm sure the Doctor will have told you of our work in the cave, and he will also have told you that we now realise what's made so many of these mutations to go wrong.
INVESTIGATOR: Wrong? But the Doctor has said it was a natural process. Why wrong?
SONDERGAARD: Well, you see
MARSHAL: There you see? Even Sondergaard admits it. The mutants are evil! Must be destroyed!
(Down on Solos, a mutant finally gets into a transfer cubicle and activates it. Up on Skybase it goes off looking for Sondergaard.)
SONDERGAARD: I beg not to listen to this man. The mutants are not monsters. They are the native life form of this planet, undergoing a natural and inevitable change. This change, however, has been brought about prematurely by that man's rash and callous experiments!
JAEGER: That's a lie! Where's your evidence?
(The mutant enters.)
MARSHAL: Mutts!
SONDERGAARD: No! There's nothing to be afraid of. The mutants are not dangerous unless you try to harm them.
MARSHAL: They're evil! Don't deserve to live!
SONDERGAARD: That is a rational and intelligent creature. To kill it would be murder!
MARSHAL: Destroy it or we'll all be killed!
KY: No!
(Ky tries to grab a weapon but is knocked down. The mutant leaves, the Marshal takes a weapon and fires at it.)

[Outside the Marshal's office]

(The Marshal guns down the mutant. The Investigator approaches.)
MARSHAL: There, you see what I have to deal with? More of these creatures may attack us. I want my men released at once. Now! And your men placed under my command.
(An ECS guard runs up.)
INVESTIGATOR: Release the Marshal's men. Obey his orders during this emergency.
MARSHAL: You others follow me.

[Marshal's office]

(Cotton is helping a suffering Ky.)
JAEGER: They've gone.
MARSHAL: What? Who?
JAEGER: The Doctor, his assistant, Sondergaard. These two weren't quick enough.
MARSHAL: Right, after them. To the laboratory. Seal all exits. Take these two to the radiation chamber.
JAEGER: But what about the radiation level? After refuelling, it'll be much higher than
MARSHAL: That's their problem, isn't it? Take them away.

[Skybase One Laboratory]

DOCTOR: Jo, take this key. Lock the door.
JO: Right.
SONDERGAARD: Doctor, the crystal, the one you found in the cave. You have it still?
DOCTOR: Yes, yes, of course.
(The Doctor takes it from his cape, still hanging over the railing.)
DOCTOR: Yes. Now, all we've got to do is analyse its structure.
SONDERGAARD: But that would take hours.
DOCTOR: Yes, well, we haven't got hours, but we do have this. It will help me to accelerate the process, I think.
(The Doctor attaches the crystal to the particle reverser.)
JO: Well, quickly, Doctor!
DOCTOR: I'm being as quick as I can, Jo.
(The crystal glows brightly.)
DOCTOR: Yes, of course. Of course! The crystal acts as a bio-catalytic agent. Sondergaard, take this crystal to Ky immediately. But what about the thaesium radiation? Surely that's the vital part of the process?
JO: Well, there's thaesium radiation in the chamber where they took us. Cotton told me.
DOCTOR: Well, what else can we do? We must try it. If we hope to achieve a successful mutation, that is.
(The door lock blows up and the Marshal enters with guards.)
MARSHAL: Get away from that machine, Doctor. Guards, take that girl and Sondergaard to the radiation chamber.
DOCTOR: So, you've managed to wriggle out of trouble, have you?
MARSHAL: I am once more in full control of Skybase, Doctor. A fact you would do well to remember.
DOCTOR: Congratulations. Well, what do you want now?
MARSHAL: An Earth type atmosphere on Solos. Nothing more, nothing less. Your friends will be confined to the radiation chamber while you work. I am afraid the radiation is at a dangerously high level at the moment, so you'd better hurry, Doctor.

[Skybase One]

(Ky is on the floor, twitching. Sondergaard and Jo are pushed in through the hatch.)
COTTON: I'm afraid Ky's just about had it, Miss.
SONDERGAARD: How long has he been like this?
COTTON: It started as soon as we got in here. The first dose didn't do him any good. Now this lot on top.
SONDERGAARD: The first dose? Oh yes, you were confined here before, weren't you? Well, we'll have to hurry. We may already be too late.
(Sondergaard places the crystal in Ky's hands.)
COTTON: Now what?
SONDERGAARD: We wait.
COTTON: We can't wait too long.
(Ky thrashes about suddenly.)
JO: Ky!
SONDERGAARD: No, no, leave him.
JO: Look, he's changing.
(Ky mutates very quickly, before their eyes.)

[Skybase One Laboratory]

(Jaeger enters.)
MARSHAL: Watch him, Jaeger. That's about all you're good for, so watch him like a hawk.
(The Doctor works on the particle reversal equipment. The Investigator enters.)
INVESTIGATOR: Marshal!
(Jaeger turns to look and the Doctor switches a couple of leads over.)
MARSHAL: Investigator.
INVESTIGATOR: Why have my men been disarmed and confined to their quarters? What is this nonsense about my ship not being allowed to leave Skybase?
MARSHAL: Oh, no nonsense, Investigator. I'm sure you and your crew will enjoy your stay on Solos.
INVESTIGATOR: Solos?
MARSHAL: Yes, as soon as our good friend the Doctor here has finished his twiddling, Solos will find itself with a new atmosphere. You and the others will be the first settlers on New Earth.
INVESTIGATOR: And you, Marshal?
MARSHAL: I shall rule from Skybase.
INVESTIGATOR: You will never be allowed
MARSHAL: Oh, come now. You didn't think I'd let you return to Earth Council? An accident will be reported. Lost with all hands I believe is the phrase.
INVESTIGATOR: Other ships will come from Earth.
MARSHAL: Oh, they'll be room for them. You should be grateful to help me. We'll begin a new Earth, the centre of a new empire.
DOCTOR: It's all right, Investigator. He's quite mad.
MARSHAL: Oh no, Doctor. I told you. Madmen lose. I've won. Solos is mine. Have you finished your work?
DOCTOR: Almost. And my companions?
MARSHAL: Will be released as soon as the job is done.

[Radiation chamber]

(The mutated Ky is glowing.)
JO: Why is he drawing all the radiation?
SONDERGAARD: I don't know, my child. We can only watch and hope.
(There is a bright flash and a beautiful person in long flowing robes emerges from the chrysalis, a rainbow of colours drifting over him.)
SONDERGAARD: It worked. Thank heavens, it worked!
COTTON: Worked?
SONDERGAARD: Yes.
JO: Ky? Ky, can you hear me?
(Ky is now a telepath.)
KY [OC]: I hear you.
SONDERGAARD: It's thought transference. That's wonderful, wonderful!
COTTON: Yeah, marvellous. But can he get us out?
KY [OC]: There is little I cannot do now. Ky thanks you, Professor Sondergaard. You have saved my people. You have shown the way. Goodbye.
(Ky floats out through the wall.)
JO: Ky!
COTTON: Goodbye? Great, innit? He just flashes off and leaves us here.
(The entry hatch swings open.)
SONDERGAARD: Out, quickly. Help Miss Grant.
(Ascended Ky floats through Skybase. He waves his arms as he passes two guards and they collapse.)

[Skybase One laboratory]

(The Marshal is guarding Jaeger, the Doctor and the Investigator on his own.)
MARSHAL: Are we ready?
DOCTOR: Yes.
MARSHAL: Very well.
(The Doctor goes over to the atmosphere control machine.)
DOCTOR: You do realise, Marshal, that you're about to destroy a life form unique in the history of the universe?
MARSHAL: Hurry, Doctor, hurry.
DOCTOR: As you wish.
MARSHAL: Wait.
DOCTOR: Change of heart, Marshal?
MARSHAL: I still don't trust you. Jaeger?
(Jaeger takes the Doctor's place at the controls. The Doctor leads the Investigator back to a safer distance. At the Marshal's nod, Jaeger switches on. Smoke then flames start to come out of the machine.)
MARSHAL: Jaeger! Stop it!
JAEGER: I can't! It's overloading!
DOCTOR: Get down.
(The machine explodes, killing Jaeger.)
DOCTOR: Right, out!
(The Doctor and the Investigator head for the door.)
MARSHAL: Doctor, you have destroyed my dreams! I'll destroy you!
(Ky appears, standing over the particle reverser.)
KY [OC]: Die, Marshal. Let there be an end to your torture of my people.
(Ky sends a beam of energy to the Marshal, who vapourises.)
KY [OC]: I thank you, Doctor, for all my people. Goodbye.
(Ky vanishes.)

[Marshal's office]

DOCTOR: Professor Sondergaard has agreed to stay on Solos and see as many of the Solonians as possible through to the stage that Ky has already achieved.
JO: But what about the others, the mutants we saw in the caves?
DOCTOR: They were premature mutations, Jo. The cycle of changes was triggered off too soon. Rather like butterflies that hatch out on a cold spring day. Their instincts were too confused to seek out and use the crystal.
JO: And now you think you'll be able to help them?
SONDERGAARD: Oh yes, we think so. Ky is on Solos now and, with the crystal, we hope we can save them.
JO: And what are you going to do, Cotton?
COTTON: Give Ky and Professor Sondergaard all the help I can. Try and clear up some of the mess the Marshal made. Then, do something we should have all done a long time ago.
JO: What's that?
COTTON: Go home, Miss. Back to Earth.
INVESTIGATOR: Exactly. Cotton, you will assume acting command of this base, pending its return to Earth.
COTTON: Sir.
INVESTIGATOR: I take it you will be returning in Hyperion with me? I still require a full account of your involvement in this affair.
DOCTOR: Yes, yes, of course, but I wonder whether you'd excuse us for the moment, Investigator? My assistant is feeling rather faint.
JO: Who, me? No, I'm fine now, honestly. I didn't feel too good earlier, but
DOCTOR: No, Jo, no you have been rather overdoing it, you know, and you
JO: I have?
DOCTOR: You don't look too well.
JO: Really?
DOCTOR: Come on. Will you excuse us? We'll see you all, later.
(The Doctor and Jo leave.)
INVESTIGATOR: Doctor, who did you say?

[Skybase One storage area 4]

DOCTOR: Well, here we are.
JO: Where?
DOCTOR: The storage area where we left the Tardis.
JO: Oh!
(But this door will not open to his palm print.)
DOCTOR: Oh, no. They've locked it again.
JO: More breaking and entering?
(Jo holds up the sonic screwdriver.)
DOCTOR: Give me that.
(A quick buzz and the door opens.)
JO: Oh well, back to the broom cupboard.
DOCTOR: Yes, well at least we've made a clean sweep of this place. Jo?
(Chuckling, they enter the storage room. A klaxon sounds.)
MAN [OC]: Attention! Attention! Computer confirms malfunction in storage area four. Investigate, please. Investigate, please.
(The Tardis dematerialises.)

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