Part One

[Brendon Public School]

(Welcome to Trent Park, Enfield Chase, Middlesex, and a lovely view of the obelisk through the trees. A group of boys are doing a cross country run while another is lovingly polishing the bonnet of a grand old motor car, registration JA566. Note for non-British - a Public School in the UK is an expensive fee-paying establishment. Think Eton or Winchester.)

IBBOTSON: A 1929 Humber 16/50 open tourer, Imperial model. Do you realise this car has the same chassis as the three and a half litre Humber Super Snipe?
TURLOUGH: Crude, heavy and inefficient.

(Everyone say Hi! to Mark Strickson.)

IBBOTSON: This car is a classic, Turlough.
TURLOUGH: It's dull and fat and ugly. Just like you, Hippo.

(Turlough opens the passenger's door.)

IBBOTSON: Turlough!
TURLOUGH: We're going for a ride.
IBBOTSON: You can't drive the car!
TURLOUGH: Watch me.
IBBOTSON: We'll be caught.
TURLOUGH: Who will know?
IBBOTSON: Oh, Turlough, we can't.
TURLOUGH: Oh, come on, Hippo. Just to the end of the drive and back. You're not afraid, are you? Come on.

(Turlough pushes Ibbotson into the vehicle.)

IBBOTSON: Turlough!

(Turlough gets behind the steering wheel, starts the engine, puts it into gear and drives off to cheers from the watching boys. Out he goes through the main gates and onto the public road.)

[Car]

IBBOTSON: Hey, you said just to the end of the drive. But you haven't got a license, Turlough.
TURLOUGH: So, who needs one?
IBBOTSON: Oh, go back to the school, please. Oh Turlough, slow down, please. You're on the wrong side of the road, Turlough!
TURLOUGH: This car's a classic. Isn't that what you said, Hippo?
IBBOTSON: Look out!

(They meet a van coming the other way on the single track road. There is a screech of brakes and Turlough steers the Humber through a break in the hedgerow and into a field. Then we get treated to a special effect and an aerial view of the accident victims being treated by the police, a doctor and a couple of gowned masters.)

[Limbo]

(The out of body Turlough is joined by Valentine Dyall wearing a dead black chicken on his head. Everyone remember the Black Guardian from the Key to Time season?)

TURLOUGH: Who are you?
GUARDIAN: A friend.
TURLOUGH: What is this place?
GUARDIAN: There's no need to be afraid.
TURLOUGH: Then tell me who you are.
GUARDIAN: Your guardian. One who has your interests at heart.
TURLOUGH: Am I dead?
GUARDIAN: Merely sleeping.
TURLOUGH: I don't think I'd really care if I were. I hate Earth.
GUARDIAN: You would like to leave?
TURLOUGH: Is it possible?
GUARDIAN: All things are possible.
TURLOUGH: Then get me away from here, please.
GUARDIAN: But first, we should have to discuss terms.

[Field]

RUNCIMAN: He'll be all right. No bones broken. Just a slight concussion.
HEADMASTER: It's a wonder they weren't both killed. What's the damage at your end, Brigadier?

(Alistair Lethbridge Stewart, no longer in uniform, looks up from the wreckage of his motor car. It should have been Ian Chesterton, but circumstances prevented. Shame.)

BRIGADIER: Eh? In thirty years of soldiering, I've never encountered such destructive power as I have seen displayed here and now by the British schoolboy. Well, how is he?
RUNCIMAN: He's been lucky, He'll be all right.

[Limbo]

GUARDIAN: We haven't much longer. I need to know that I have your assent to our arrangement. You will find me the most accommodating of partners.
TURLOUGH: But murder. I'm not sure I could go that far.
GUARDIAN: You will be destroying one of the most evil creatures in the universe. He calls himself the Doctor.
TURLOUGH: Why can't you destroy him? You have the powers.
GUARDIAN: I may not be seen to act in this. I must not be involved.
TURLOUGH: I need time to think.
GUARDIAN: There is no time. Yes or no?
TURLOUGH: Don't send me back to Earth, please.

(Turlough begins to fade.)

GUARDIAN: Yes or no?
TURLOUGH: Yes.

(Turlough vanishes. The Black Guardian laughs his deep, evil laugh.)

[Field]

(Turlough begins to wake, thrashing around.)

RUNCIMAN: He's coming round.
BRIGADIER: Steady on, old chap. You had a bit of a knock.

[TARDIS]

TEGAN: Doctor? I am free of the Mara, aren't I?
DOCTOR: Tegan, Tegan, Tegan.
TEGAN: I'm scared.
DOCTOR: There isn't any need to be.
TEGAN: I'm still having terrible dreams.
DOCTOR: It's your mind's way of coping with the experience. You've suffered a great deal.
TEGAN: That could have been prevented if that Dojjen person had destroyed the Great Crystal.
DOCTOR: No, he couldn't. The Mara during the process of its becoming. It had to be trapped between modes of its being.
TEGAN: The feelings of hate. Doctor, I couldn't go through it again.
DOCTOR: Well, you're completely free of it now, Tegan. For you, the Mara is dead forever.
NYSSA: For all of us, I hope.

(Nyssa has changed the gaudy outfit of the previous story for a denim mini-dress and flat mid-calf boots.)

DOCTOR: Indeed.
TEGAN: Can you take me back to Earth?
NYSSA: You want to leave us?
TEGAN: I want to rest. I want to be surrounded by familiar things.
NYSSA: You'll forget the Mara, Tegan. It won't always be as painful as it is now.

(The TARDIS jerks, throwing them sideways.)

DOCTOR: Warp ellipse cut out?
NYSSA: Can't be. That would mean we were near an object in a fixed orbit in time as well as space.
DOCTOR: And what's the probability of that?
NYSSA: Several billion to one against.
TEGAN: Are you trying to scare me, or is this your way of telling me we've broken down again?
DOCTOR: I'm afraid it's much more serious than that.

[Sickbay]

MATRON: Right, into bed with you, young man.
TURLOUGH: Oh, Matron, I'm perfectly all right.
MATRON: Mild concussion and shock. You heard what Doctor Runciman said. We don't want complications, do we?
TURLOUGH: I'm not going to bed.
MATRON: Just this once you can do as you're told. You're in enough hot water already.

(Turlough obeys, then sees a curious crystal on the bedside table.)

TURLOUGH: Matron, where did this come from?
MATRON: It was in your jacket, and that was in a fine old mess, I don't mind telling you.

(The Headmaster enters. Turlough puts the crystal under his pillow.)

MATRON: Good afternoon, Headmaster.
HEADMASTER: Is it, I wonder. Well, Turlough, how are you feeling?
TURLOUGH: Much better, thank you, sir.
HEADMASTER: Which is more than the Brigadier can say for his car. I don't understand you. You make no effort at games, you refuse to join the CCF, you do little or no work in class though you have a first-rate mind, and now this.
TURLOUGH: I wasn't driving, you know, sir.
HEADMASTER: What?
TURLOUGH: The Brigadier's car.
HEADMASTER: But Ibbotson said
TURLOUGH: I didn't want Ibbotson to get into trouble, sir. I only went along in case he got hurt. I knew he wasn't really able to drive it, and, well
HEADMASTER: I see.
MATRON: Ahem. Turlough must get some sleep, Headmaster.
HEADMASTER: Of course, Matron. I'll look in again later.

(The Headmaster and Matron leave. Turlough gets the crystal out and looks at it. Suddenly it glows.)

TURLOUGH: So you are real. I thought it was just a dream.
GUARDIAN [OC]: Waking or sleeping, I shall be with you until our business is concluded.

[TARDIS]

NYSSA: Are we safe?
DOCTOR: There's a chance something's on a collision course with the TARDIS.
TEGAN: Don't you know?

(Nyssa turns on the scanner.)

DOCTOR: Well, there's a chance of anything. Statistically speaking, if you gave typewriters to a tree full of monkeys, they'd eventually produce the works of William Shakespeare.
NYSSA: Doctor!
DOCTOR: Now, you and I know that at the end of the millennium they'd still be tapping out gibberish.
DOCTOR: And you'd be tapping it out right along side them. I only asked you a simple question.
NYSSA: Doctor, something's coming straight for us!

(The sharp prow of a spaceship is bearing down on the TARDIS.)

NYSSA: We've got to get out of the way.
DOCTOR: We can't. We've converged with the warp ellipse.
NYSSA: Doctor!
DOCTOR: Hold this steady.
TEGAN: We're going to crash.
DOCTOR: I'll try and materialise on board the ship. Hold tight!

(The TARDIS materialises on the marble floor of a very posh room.)

[Sickbay]

TURLOUGH: Why am I still on Earth?
GUARDIAN: Patience, Turlough. Already the elements of chance are ranged against the Doctor. Soon he will be separated from the TARDIS and in your power. Go to the hill, boy, to the obelisk, and wait. There I will instruct you further.

[Outside the Headmaster's study]

HEADMASTER [OC]: You realise, Ibbotson, what you did is a criminal offence. If it weren't for the good name of the school, I'd hand you both over to the police.

(A pair of passing boys find this fascinating and stop to listen at the door.)

HEADMASTER [OC]: I shall be writing to your parents, needless to say.
BRIGADIER: Ahem.

(The boys leave. Ibbotson leaves the study and bumps into the Brigadier.)

BRIGADIER: Ah, Ibbotson. And what have you got to say for yourself?
IBBOTSON: Please, sir, I'm very sorry, sir, but it wasn't my fault, honestly. I'm really sorry, sir.

(Ibbotson leaves and the Headmaster comes out.)

BRIGADIER: Ah, Headmaster. I trust you flogged that young man within an inch of his life?
HEADMASTER: Thank you, Brigadier, but I feel that we should wait until Turlough is restored to health before we take any legal or disciplinary action.
BRIGADIER: You realise that car was unique?
HEADMASTER: Quite, but I feel sure that you will agree that we must do what is best for the school.
BRIGADIER: Yes, well. Oh, if you say so, Headmaster. Mind, you can't really take it out on Ibbotson. It's my view that he was led into this by Turlough. Oh, we've got a rotten one there.
HEADMASTER: I'm not so sure. I had a word with Turlough. He said he only went along to protect Ibbotson.
BRIGADIER: Pah. Cunning as a fox. You don't believe him, of course.
HEADMASTER: I don't know. I'd be reluctant to jeopardise the boy's future.
BRIGADIER: Have you spoken to his parents?
HEADMASTER: I thought you knew. They're dead. I deal with a solicitor in London, and a very strange man he is, too.

[Sickbay]

(Turlough pretends to sleep as the door opens.)

IBBOTSON: Are you awake, Turlough?
TURLOUGH: What do you want?
IBBOTSON: Listen, the Head's going to write to my parents. The police may be called into investigate. We could be expelled.
TURLOUGH: It's all right, Hippo. I've spoken to the Head. I told him it was all my fault.
IBBOTSON: I say, did you really, Turlough?
TURLOUGH: So you won't get the boot, just beaten, I expect.
IBBOTSON: Oh. Well, they'll beat you when you're better.
TURLOUGH: Oh no, they won't.

(Turlough throws back the bedclothes to reveal he is fully dressed. He takes the crystal and heads for the door.)

IBBOTSON: Hey, you can't get up until Doctor Runciman says so.
TURLOUGH: Goodbye, Hippo.
IBBOTSON: Oh, Turlough, you can't leave me on my own! Oh please, Turlough!

[Spaceship]

TEGAN: Strange ship.
NYSSA: No sign of any passengers.
TEGAN: Probably having cocktails with the Captain.
NYSSA: What?
TEGAN: Well, I mean it's more like the Queen Mary than a spaceship.

(They walk on a little way.)

TEGAN: I take it back. It's not the Queen Mary, it's the Marie Celeste. You'd think on a long journey they'd want something a little more cheerful.

(The Doctor walks into a corner that suddenly lights up to reveal gold busts in niches. He steps out and the lights go out again. Then they go over to what seems to be a games machine which is beeping to itself.)

NYSSA: Everything on this ship is designed for pleasure.
DOCTOR: I have a weird feeling the warp ellipse will be travelling for a very long time. Possibly through infinity.
NYSSA: Well, it's certainly no prison ship.

(No, it sounds more like the Flying Dutchman.)

[Obelisk hill]

IBBOTSON: Where are we going?
TURLOUGH: Don't ask questions.

(Turlough runs on while Ibbotson gets his breath.)

TURLOUGH: (sotto to crystal) What am I supposed to do?

(Ibbotson catches up.)

IBBOTSON: Oh, Turlough, what's happening? Who are you talking to?

(Turlough runs on again to the obelisk.)

IBBOTSON: Oh, wait for me.

[Spaceship bridge]

(The Doctor goes to a console on a raised dais.)

TEGAN: Could you fly this thing, Doctor?
NYSSA: You don't fly a ship like this, it's in perpetual orbit.
DOCTOR: Amazing.
NYSSA: Doctor?
DOCTOR: There's a length of flight indicator. This ship's been in orbit three thousand years.
TEGAN: No wonder there's no one on board.

[Obelisk hill]

(Ibbotson finally catches up with Turlough at the seat by the obelisk.)

IBBOTSON: Now what?
TURLOUGH: We wait.
GUARDIAN [OC]: The base of the urn. Press it. Release the camouflage screen protecting the capsule.

(Turlough goes over to a large stone urn on a pedestal nearby.)

[Spaceship bridge]

(Nyssa goes to a round monitor on a pole in an alcove.)

NYSSA: Doctor, look at this.
DOCTOR: Mmm. Transmat terminal.
NYSSA: And in the transmit mode.
TEGAN: The crew escaped in a life raft?
DOCTOR: Well, someone certainly left the ship, almost six years ago.
TEGAN: Where to?
DOCTOR: Earth.

(The transmat monitor agrees. Alpha = 960 Beta = 960 Gamma = 960 Destination Earth Constant Vector .67.893 Sub-coordinate 8284.64892 Warp Differential .47298? last figure lost in the curve of the monitor.)

[Obelisk hill]

(Turlough pushes a panel at the base of the urn and a few moments later an egg-shaped capsule appears in the bushes nearby.)

IBBOTSON: What is it?
TURLOUGH: A transmat capsule. Don't you know anything?

[Spaceship bridge]

DOCTOR: The ship's orbit takes it within range of Earth for six years.
TEGAN: Someone might come back.
DOCTOR: Any time. Come on, let's get back to the TARDIS.

[Obelisk hill]

IBBOTSON: Keep back!

(The capsule door opens and Turlough goes inside. It closes after him.)

IBBOTSON: Turlough!

(The capsule vanishes. Ibbotson runs back down the hill.)

[Spaceship bridge]

(Turlough steps out of the capsule and up to the console. He takes out the crystal.)

GUARDIAN [OC]: The controls of the vessel are of no interest to you, Turlough.
TURLOUGH: But it's a ship! I can get home!
GUARDIAN [OC]: I did not bring you here so that you could return home. Your concern is with the Doctor.

(Turlough tries to throw the crystal away, but it is stuck to his hand. The Black Guardian appears in a flash.)

GUARDIAN: You will obey me in all things.
TURLOUGH: Let me go.
GUARDIAN: Remember the agreement between us.
TURLOUGH: Yes.
GUARDIAN: You will seek out the Doctor and destroy him.
TURLOUGH: Of course. I will seek out the Doctor and destroy him.

[Spaceship]

DOCTOR: Quickly.

(The girls catch up to him and they go inside the TARDIS.)

[Brendon Public School]

IBBOTSON: Sir! Sir!

(The Brigadier watches Ibbotson run up to the terrace.)

IBBOTSON: It's Turlough, sir.
BRIGADIER: What?
IBBOTSON: We were on the hill, sir, and there was this great big silver ball, and Turlough went inside and disappeared.

[TARDIS]

(The console beeps at the Doctor.)

TEGAN: Now what?
DOCTOR: The TARDIS won't dematerialise.

(He tries hitting it. This time it does not work.)

[Obelisk hill]

BRIGADIER: If you took more regular exercise, Ibbotson, not only would your body be less disgusting, but you'd enjoy a healthier imagination.
IBBOTSON: I didn't imagine it, sir.
BRIGADIER: Take it from me, boy, a solid object just can't dematerialise. Turlough!

[TARDIS]

TEGAN: What's happening?
DOCTOR: I wonder.

(The Doctor goes underneath the console as Turlough arrives outside.)

DOCTOR: I might have known.
NYSSA: Doctor?

[Spaceship]

TEGAN: Where are you going?

(The girls run off after the Doctor, and Turlough comes round from the back of the TARDIS and goes inside.)

[Spaceship bridge]

DOCTOR: The transmat beam, it's been operated. The signal is interfering with the TARDIS.
NYSSA: Look. It must have just returned.
TEGAN: Well, how is the transmat signal jamming us?
DOCTOR: Well, the capsule and the TARDIS must be dimensionally very similar, and the beam's still functioning. It's supposed to cut out when the capsule completes its journey.
TEGAN: Well, can you switch it off?
DOCTOR: I hope so.
TEGAN: I hope so too. I don't fancy a non-stop mystery tour of the galaxy.
DOCTOR: Ah.
NYSSA: You found the fault?
DOCTOR: In a manner of speaking. It's on Earth.
TEGAN: Earth?
DOCTOR: If these readings are correct, it's 1983 on Earth.
TEGAN: So?
DOCTOR: Well, the capsule originally left the ship six years ago.
TEGAN: 1977.
DOCTOR: Yes. I wonder what it's been up to all that time. Come on, back to the TARDIS.
TEGAN: Doctor, wait.
NYSSA: What's the matter?
TEGAN: Well, if that thing's back, then someone could be on board the ship.

[TARDIS]

(Turlough is at the controls as the Doctor runs in. A few moments later they look up at each other across the console.)

DOCTOR: Who are you?

[Sickbay]

HEADMASTER: Turlough again.
MATRON: I'm sorry, Headmaster, but he was missing when I came in with Doctor Runciman. And there's no sign of Ibbotson either.
HEADMASTER: I must talk to the Brigadier.
MATRON: I sent a boy round to his quarters, but the Brigadier's disappeared too.

[TARDIS]

(The Doctor enters from the interior carrying a case.)

DOCTOR: This is Turlough.
TEGAN: Where did you come from?
DOCTOR: The transmat capsule.
TEGAN: Earth?
TURLOUGH: The capsule just appeared. It was very strange.
NYSSA: And you just walked in?
DOCTOR: Seven, eight. All set.
NYSSA: Where are you going?
DOCTOR: Earth, via the transmat capsule.
TEGAN: Is it safe?
DOCTOR: Well, it worked one way. Once I've disconnected the beam jamming the TARDIS, you should follow me through to Earth.
TURLOUGH: May I come with you?
DOCTOR: You'll be safer in the TARDIS.
TURLOUGH: Please?
DOCTOR: All right, why not. See you on Earth.
NYSSA: Good luck.

[Transmat capsule]

(Which is also dimensionally transcendental and as opulent as the spaceship, appears by the obelisk.)

DOCTOR: Come on.

[Obelisk hill]

DOCTOR: It's a pity those things don't have a wider range. Still, at least we're here in one piece. Transmat capsules can do very nasty things to organic structures if they're not properly maintained.

(The Doctor's detector leads him to the base of the urn.)

[TARDIS]

(Tegan and Nyssa bring in a pair of wicker stools.)

TEGAN: I don't trust that boy.
NYSSA: Oh, I don't know. I thought he was rather nice.
TEGAN: Nobody from Earth is just going to walk into a transmat capsule.
NYSSA: As you did into the TARDIS on the Barnet bypass?

[Obelisk hill]

(The Doctor opens the base of the urn and takes out the transmat control unit. Turlough moves away.)

[Limbo]

GUARDIAN: In the name of all that is evil, the Black Guardian orders you to destroy him now!

(Turlough picks up a head-sized stone and sneaks up behind the Doctor.)

GUARDIAN: Now, boy. Do it now!

(Turlough raises the stone above his head.)

Part Two

[Obelisk hill]

(The Doctor gets the transmat control unit open.)

DOCTOR: Done it.

(Bang! The unit explodes, throwing them both backwards. Turlough drops the stone.)

[TARDIS]

(The time rotor starts moving up and down.)

TEGAN: Here we go.

[Obelisk hill]

DOCTOR: Well, that shouldn't have happened.

(The TARDIS materialises briefly on a path nearby, then vanishes again.)

TURLOUGH: What's happened? Could it have been affected by tangential deviation coming out of the warp ellipse?
DOCTOR: Not with the dead reckoning alignment in the coordinates. This is 1983?
TURLOUGH: Yes.
DOCTOR: Then it should be here.
TURLOUGH: But as it isn't, where's it gone?

[TARDIS]

(The scanner shows the obelisk and urns.)

TEGAN: Where's the Doctor? Nyssa, are you sure this is the right place?
NYSSA: It should be.
TEGAN: Something's wrong, isn't it.
NYSSA: I don't know. I'm sure the Doctor's only wandered off.

[Obelisk hill]

TURLOUGH: Will your friends be safe?
DOCTOR: I hope so. Now, what did I do wrong?

(Turlough goes into the bushes to talk to his crystal.)

TURLOUGH: What do I do now? Say something!
BRIGADIER: Turlough!

[Obelisk hill 2]

NYSSA: Doctor? Doctor?
TEGAN: There's no one here.

[Obelisk hill]

BRIGADIER: Ah, so there you are, Turlough.
TURLOUGH: Sir.
IBBOTSON: What happened? The sphere
BRIGADIER: Oh do be quiet, boy. You're supposed to be in the sickbay.
TURLOUGH: I was with the Doctor.
BRIGADIER: Doctor? What, Doctor Runciman?
TURLOUGH: No, sir. This Doctor.
DOCTOR: Brigadier. Brigadier Alistair Gordon Lethbridge Stewart.
BRIGADIER: Well, who are you?

[Obelisk hill 2]

TEGAN: Down there in the valley.
NYSSA: I think I saw someone move.
TEGAN: It can't be the Doctor. There hasn't been time enough for him to get that far. Maybe the capsule's malfunctioned? I hate those transmat things. Like travelling in a food mixer, and just as dangerous. I'd be afraid of coming out pureed.

(The transmat capsule arrives.)

NYSSA: Look.

[Transmat capsule]

(A badly burnt person is lying on the floor, wearing mere shreds of clothing.)

TEGAN: Doctor! Look at the state he's in. What are we going to do?
NYSSA: Tegan, we mustn't panic.
TEGAN: He could die. Doctor, what happened?

(But we can see this is clearly not the Doctor. Everyone say Hi! to David Collings, making a return appearance.)

MAWDRYN: Where am I?
NYSSA: You're on Earth, Doctor. You came in the transmat capsule.
MAWDRYN: Earth?
TEGAN: We followed you through in the TARDIS. Do you remember?
MAWDRYN: TARDIS?
NYSSA: It's outside. Let me help you.
MAWDRYN: TARDIS.
NYSSA: Doctor.
MAWDRYN: Help me. Help me into the TARDIS.

[Obelisk hill]

BRIGADIER: Well, I'm sorry. If we have met before, it's entirely slipped my memory, and I've got to get these boys back to school. Come on, you two.

(The Doctor smiles, and follows.)

[TARDIS]

(Tegan and Nyssa drag the unconscious man into the TARDIS.)

TEGAN: I'll get some clothes for him.
NYSSA: Don't you think we should get him into a bed?
TEGAN: It's too risky to move him again. Go and find some blankets. We must keep him warm.

(Nyssa leaves.)

TEGAN: It's all right, Doctor. You're safe inside the TARDIS.

[Outside the Headmaster's study]

(Ibbotson knocks on the door.)

HEADMASTER [OC]: Come in.

(Ibbotson obeys.)

DOCTOR: Brigadier?
BRIGADIER: Oh, it's you.
DOCTOR: I'd forgotten.
BRIGADIER: I beg your pardon?
DOCTOR: I've regenerated.
BRIGADIER: Really.
DOCTOR: What would you say if I told you I was looking for my TARDIS?
BRIGADIER: Very little.
DOCTOR: What about our time together with UNIT?
BRIGADIER: What?
DOCTOR: So you do remember.
BRIGADIER: UNIT is a secret organisation. If you are aware of its existence, you would almost certainly have signed the Official Secrets Act.
DOCTOR: Is there somewhere we could talk?
BRIGADIER: Oh, very well. My quarters. This way.

[TARDIS]

(Mawdryn has a pillow under his head, and Nyssa is covering him with a blanket and Tom Baker's big red coat.)

TEGAN: I think he's unconscious.
NYSSA: Something must have happened to the capsule.
TEGAN: I told you those things were dangerous.
NYSSA: That boy!
TEGAN: Turlough. I forgot about him. Stay here.

(Turlough has been locked in the sickbay.)

[Walled garden]

DOCTOR: An undercover operation, is it, Brigadier? I mean, I hardly expected to find you at a boy's school.
BRIGADIER: Huh.

[TARDIS]

MAWDRYN: Stability not achieved. Our transmat projection was destructive. Stability not achieved. No end.
NYSSA: You're safe now, Doctor.

(Tegan runs in.)

TEGAN: No sign of Turlough.
NYSSA: He could have been atomised.

[Outside the Brigadier's quarters]

BRIGADIER: There you are. (A wooden building.)
DOCTOR: Your quarters?
BRIGADIER: Serviceable.
DOCTOR: Quite.
BRIGADIER: Well. Here we go.

(The door sticks slightly as the Brigadier tries to push it open.)

BRIGADIER [OC]: Sorry about the door.

[Brigadier's quarters]

BRIGADIER: Do go in.

(The Brigadier puts the kettle on in the kitchenette. The Doctor picks up a framed photograph of the Brigadier in uniform.)

BRIGADIER: Now then, what's all this about UNIT?
DOCTOR: Brigadier, I need your help. I've lost the TARDIS.
BRIGADIER: I don't know what the TARDIS is. I've already told you.
DOCTOR: And you don't remember me?
BRIGADIER: Certainly not. But whoever you are, I can't let you wander around blabbing about classified UNIT operations.
DOCTOR: Oh, there's much more at stake than a breach of security. I've lost my TARDIS, you've lost your memory. I'd be surprised if the two events weren't connected.
BRIGADIER: Let me tell you, sir, that I'm in full possession of all my faculties. After all, if I was suffering from amnesia, I'd be the first to know about it, wouldn't I?

[TARDIS]

TEGAN: I'm going for help.
NYSSA: Where?
TEGAN: To that building we saw. Use their phone.
NYSSA: If only we still had the Zero room. Its restorative power would have helped.
TEGAN: Well, as we haven't, a hospital's the next best thing. I'm off.
NYSSA: All right. Take the homing device with you.
TEGAN: I'll be as quick as I can.

[Brigadier's quarters]

DOCTOR: By the way, how's Sergeant Benton these days?
BRIGADIER: Oh, left the army in 79. Sells second hand cars somewhere.
DOCTOR: And Harry Sullivan?
BRIGADIER: Seconded to NATO. Last heard of doing something very hush-hush at Porton Down.
DOCTOR: Do you ever see anything of Jo Grant?
BRIGADIER: What?
DOCTOR: My assistant, Jo Grant.
VOICE [OC]: Jo Grant.
BRIGADIER: Jo Grant?
DOCTOR: Sarah Jane?
VOICE [OC]: Sarah Jane.
BRIGADIER: Sarah Jane?
DOCTOR: Liz Shaw you'll remember, of course.
VOICE [OC]: Liz Shaw.
BRIGADIER: Liz Shaw?
DOCTOR: Are you all right?
BRIGADIER: Someone just walked over my grave.
DOCTOR: Perhaps it was a yeti, Colonel Lethbridge Stewart.

(The voices whisper the companion's names, overlapping. We are shown sepia images from an Abominable Snowman episode, an early Cyberman and Patrick Troughton, Axons, Daleks, Jon Pertwee with smoke pouring from the TARDIS, William Hartnell on the TARDIS monitor from Three Doctors, the Robot, a Zygon and Tom Baker then back to the Brigadier's first wondering look inside the TARDIS.)

DOCTOR: One lump or two, Brigadier?
BRIGADIER: Well, bless my soul. So you've done it again, Doctor.

(One lump, then. Meanwhile, in the world where the Doctor isn't, Tegan is running up to the main building.)

BRIGADIER: I must apologise for my cavalier behaviour when we met, Doctor.
DOCTOR: It's hardly your fault, Brigadier.
BRIGADIER: It is good to see you. Yeah, the Doctor and the TARDIS. How could I ever forget?
DOCTOR: Exactly.
BRIGADIER: What?
DOCTOR: The mental block, there must be some reason for it. Some trauma, some shocking experience, maybe some induced effect.
BRIGADIER: I don't scare quickly, Doctor. Nor do I succumb easily to brainwashing techniques.
DOCTOR: No, no, of course not. So, if there was a way of tracing how far back the inhibition goes, you could perhaps get some treatment.
BRIGADIER: Treatment? Treatment? There's nothing wrong with me, Doctor.
DOCTOR: Well, no.
BRIGADIER: A one, always have been.
DOCTOR: Absolutely.
BRIGADIER: I suppose you've been talking behind my back with Doctor Runciman.
DOCTOR: Brigadier
BRIGADIER: Oh, there's loyalty for you. It's no good. I'm not taking my leave at the funny farm. There's nothing wrong with me, I tell you. Fit as a fiddle, always have been. Sorry about that, Doctor. Had a bit of bother a while back. Overwork, you know. Doctor Runciman called it a nervous breakdown. Breakdown. Don't know the meaning of the word. This one goes on till he drops.

(The mysterious stranger starts to wake as Nyssa turns on the TARDIS scanner.)

DOCTOR: When did you leave UNIT, Brigadier?
BRIGADIER: Seven years ago. Oh, of course, I could have retired on my army pension, grown vegetable marrows and died of boredom in a twelve-month, then this job turned up. Bit of admin, bit of rugger, CO in the school corps.
DOCTOR: And you teach?
BRIGADIER: Mathematics. Oh, I know how many beans make five, Doctor, and you don't have to be a Time Lord to cope with A level maths. It may come as a surprise to you, but I also happen to like teaching.

[Brendon Public School]

(Tegan runs up to a group of boys carrying Union flags and wearing Silver Jubilee 1977 t-shirts.)

TEGAN: Hey, can anyone tell me where I can find a doctor?

[Brigadier's quarters]

DOCTOR: Well, Brigadier, much as I appreciate your company, I've still got to find my TARDIS.
BRIGADIER: (chuckles) Your TARDIS. You know, Doctor, I never believed it could do half the things you claimed.
DOCTOR: Yes, well, just at the moment I'd settle for half a TARDIS, and I'm very worried about Nyssa and Tegan.
BRIGADIER: Tegan. Tegan.
DOCTOR: What's the matter?
BRIGADIER: I knew a Tegan once.
DOCTOR: Oh, Tegan's after your time, Brigadier. She's travelling with me in the TARDIS.
BRIGADIER: Attractive girl, spirited, spoke with an Australian accent.

[1977 Outside the Brigadier's quarters]

(The Brigadier, now with dark hair and no grey, and a moustache, is tending a barrel of flowers.)

TEGAN: Excuse me.
BRIGADIER: Oh, hello there.
TEGAN: I'm sorry to disturb you, but I'm looking for a doctor. There's been an accident. Well, sort of an accident. A friend of mine and possibly one of the boys from the school, he may be hurt too.
BRIGADIER: I think you'd better come in.

[1977 Brigadier's quarters]

(A band is playing Lillibulero on the radio.)

BRIGADIER: Right, sit yourself down, young lady.
TEGAN: My name's Tegan. Tegan Jovanka.
BRIGADIER: Tegan?
TEGAN: Jovanka.

(The Brigadier turns the radio off.)

[1983 Brigadier's quarters]

DOCTOR: It is Tegan.
BRIGADIER: That's what I said.
DOCTOR: Your Tegan, my Tegan, it's the same person.
BRIGADIER: Of course, Doctor.
DOCTOR: So, Tegan, Nyssa and the TARDIS, they're all here.
BRIGADIER: Are they?
DOCTOR: Or rather, they were, if you see what I mean.
BRIGADIER: Not a hundred percent, Doctor.
DOCTOR: I must have miscalculated the offset. The TARDIS came through in the right place, but the wrong time zone.
BRIGADIER: You and that TARDIS.
DOCTOR: Now, it's vitally important you remember exactly what happened.
BRIGADIER: Oh look, it's all a long time ago, Doctor. I mean, surely what's past is
DOCTOR: Very much in the present, Brigadier. You never did understand the interrelation of time.
BRIGADIER: Not much call for that in the A level syllabus, Doctor.
DOCTOR: You have in your memory the information I need to track down the TARDIS and communicate with Nyssa and Tegan.

[Sickbay]

(Turlough is in pajamas and in bed.)

HEADMASTER: There's nothing to be afraid of, Turlough, now that you've explained everything to me.
TURLOUGH: Thank you, sir.
HEADMASTER: In fact, I'm very heartened that you felt able to confide in me like this. I must say it's a most remarkable story.
TURLOUGH: But what am I to do, sir?
HEADMASTER: It seems to me you're in something of a moral dilemma.
TURLOUGH: Sir?
HEADMASTER: You accepted a free passage home to your own people, but to fulfil your part of the bargain you have to kill this Doctor.
TURLOUGH: But I don't want to kill the Doctor.
HEADMASTER: I can see you're in a most invidious position.
TURLOUGH: Haven't I done enough to separate him from his TARDIS?
HEADMASTER: I take your point, but in your heart of hearts do you entirely feel you've completed your side of the bargain?
TURLOUGH: I suppose not.
HEADMASTER: We can't get everything we like in this world.
TURLOUGH: Oh, please help me, sir.
HEADMASTER: I'm afraid I can only put the problem in perspective for you. The final choice has got to be yours.
TURLOUGH: Well, I think I'm pulling out. The Doctor's stranded, but what's been done for me? I've been ignored. I shall try and escape in the transmat capsule. He can sort the Doctor out for himself from now on.
HEADMASTER: Is that your final decision?
TURLOUGH: Yes, sir.
HEADMASTER: Are you absolutely sure?
TURLOUGH: Yes.

(The Headmaster turns into the Black Guardian.)

GUARDIAN: Waking or sleeping, you can never escape me, Turlough.

(Turlough gets out of bed and runs for the door, but it is locked.)

TURLOUGH: No, please.

(He looks back to see himself sleeping in the bed.)

GUARDIAN: You see, wretched, duplicitous child, I know your every innermost thought.
TURLOUGH: Leave me alone, please!
GUARDIAN: I invade every particle of your being. You will never be free of me until our bond is honoured.
TURLOUGH: The Doctor isn't as you say.
GUARDIAN: I am the Black Guardian! The Doctor's good is my evil.
TURLOUGH: No!
GUARDIAN: You will absorb my will. You are to be consumed with my purpose.
TURLOUGH: No!
GUARDIAN: The Doctor shall be utterly destroyed.

(Turlough meets the Black Guardian's eyes.)

TURLOUGH: The Doctor shall be utterly destroyed.

(The Black Guardian vanishes. Turlough gets back into bed and rejoins his sleeping body.)

[1977 Brigadier's quarters]

BRIGADIER: Turlough? I don't think we have a Turlough.
TEGAN: But you must have.
BRIGADIER: Mind you, I'd better check, because I'm a new boy here myself.

(He looks through an attendance book on his desk.)

BRIGADIER: Let's see. S. T. Trevor, Trumper, Turner. Nope. No, definitely no Turlough.
TEGAN: They were travelling together when they came down on the hill.
BRIGADIER: Came down? What, do you mean a plane crash?
TEGAN: Well
BRIGADIER: Good heavens, why didn't you say so before? I'll phone the local constable. He can coordinate the rescue services.
TEGAN: Look, it's not quite like that. If we could just get some medical help and get back to the TARDIS, it'd all be
BRIGADIER: TARDIS? Did you say TARDIS?
TEGAN: Yes, but you don't understand.
BRIGADIER: I think I do, young lady. Tell me, Miss Jovanka, this friend of yours, is it by any chance the Doctor?

[Sickbay]

(Turlough wakes from his nightmare and goes to the door. It is still locked. He picks up the Guardian's crystal and wraps it in the bedclothes, then uses some clean sheets to make a rope ladder. )

[1983 Brigadier's quarters]

DOCTOR: What worries me is the level of coincidence in all this. Almost as if some cosmic influence. Still, that won't get me the TARDIS back. Now, Brigadier, we've got to establish the precise time all this happened.
BRIGADIER: Well, that's a pretty tall order, Doctor.
DOCTOR: Well, don't worry. Just relax. Think yourself back.

[1977 Brendon Public School]

BRIGADIER: I'll get a message to Doctor Runciman. He'll be up on top field for the bun fight.
TEGAN: Bun fight?
BRIGADIER: Yes, the celebrations. Ah, Powell. I've got a job for you.
TEGAN: What celebrations?
BRIGADIER: Well, the Queen's Silver Jubilee, of course.

(A boy runs up.)

BRIGADIER: Powell, get hold of Doctor Runciman and tell him to bring his gear and meet me by the Obelisk.
POWELL: Yes, sir.
TEGAN: Silver Jubilee? We're in the wrong time zone!

[1983 Brigadier's quarters]

DOCTOR: June the seventh, 1977. Well done, Brigadier. Come on.

(The telephone rings.)

BRIGADIER: Lethbridge Stewart. Have you informed the Headmaster? Then do so at once, Matron. Turlough has disappeared.

(Turlough hides from some masters before running off to the hill.)

[Sickbay]

DOCTOR: He's trying to get away in the transmat capsule. That is, if he can repair the beam transmitter.

(The Doctor picks up the blanket from the floor.)

BRIGADIER: What, Turlough?
DOCTOR: It could be done, given time.

[1977 Brendon Public School]

(Tegan activates the TARDIS homing device.)

TEGAN: Spot on.
BRIGADIER: One of the Doctor's gadgets?
TEGAN: Don't want to miss the TARDIS, do we? I've just realised. The Doctor is expecting the TARDIS to follow him through to 1983. Don't you see? The wounded thing in the capsule, maybe it isn't the Doctor after all. Come on.

[1983 Sickbay]

DOCTOR: Tegan is absolutely right. I am not in the TARDIS.
BRIGADIER: Then who is? Or do I mean, who was?
DOCTOR: You tell me, Brigadier.

[1977 Obelisk hill]

NYSSA: Tegan, come on.

[TARDIS]

(The person has got up and wrapped the blanket around himself.)

NYSSA: Doctor, you're better.

(The figure turns around. Most of the burning has gone but the face still looks deformed.)

MAWDRYN: Perpetual regeneration.
NYSSA: Regeneration? You don't mean it's happening again?
MAWDRYN: It is life without end or form. Changing, changing.
NYSSA: We've lost the Zero room, Doctor. Is there any way we can reconfigure
MAWDRYN: Do not be afraid on my account. I will regain strength soon, but for the moment my mind is clouded. You understand the navigation?
NYSSA: Well, a bit. At the moment we're still aligned with the ship.
MAWDRYN: Oh, that is well. Prepare to leave at once.
NYSSA: We can't leave without Tegan.
MAWDRYN: At once!
NYSSA: Doctor, you don't know what you're saying. Tegan'll be back soon.
MAWDRYN: At once!

(Nyssa opens the doors and goes outside.)

MAWDRYN: The Time Lords abandoned us. Perpetual torment and despair. But the ending will come soon. I, Mawdryn, shall be a Time Lord.

[Obelisk hill]

NYSSA: Quickly! We've got to take off.
TEGAN: Nyssa, that man, I don't think he's the Doctor.
NYSSA: But he is. The transmat process induced a regeneration.
TEGAN: What?
BRIGADIER: Don't worry. I know all about regeneration. I've seen it twice before. Come on.
NYSSA: So have we, and the Doctor almost died. Who is that person?
TEGAN: Brigadier Lethbridge Stewart, of course. Come on.

[TARDIS]

BRIGADIER: Doctor?

(Mawdryn has draped Tom's coat over his shoulders. He turns to reveal that his brain is visible poking out and throbbing through the top of his skull. Nyssa screams.)

Part Three

[Sickbay]

DOCTOR: Don't you see, Brigadier? The TARDIS came to Earth in 1977 and so did the transmat capsule, carrying someone from that ship in space.
BRIGADIER: And Tegan and the other girl think, or rather thought, it was you.
DOCTOR: Indeed. And what did you think?
BRIGADIER: No, Doctor.
DOCTOR: You were there.
BRIGADIER: You mustn't make me remember.
DOCTOR: You must. I need the information to protect Nyssa and Tegan.
BRIGADIER: Even if I wanted to, I simply couldn't recall it.
DOCTOR: That experience could be the reason for your nervous breakdown.
BRIGADIER: Good heavens. Do you think so?

(The Doctor finds the Guardian's crystal in the blanket.)

DOCTOR: Now. Come on. We've got to get back to the capsule before Turlough works out how to operate it, or I may never get the TARDIS back.

(Turlough is already inside the transmat capsule.)

[TARDIS]

TEGAN: You're not the Doctor.
MAWDRYN: You travel with a Time Lord and know nothing of metamorphosis.
TEGAN: Yes, but it wasn't like this before. When he changed, he turned into a human.
MAWDRYN: Yes, a Gallifreyan human.
TEGAN: He was normal.
MAWDRYN: What do you know, prattling Earth child, of the endless changing?
TEGAN: I know that when the Doctor changed, he didn't turn into an alien.
MAWDRYN: The transmatting induced a mutative catalysis.
TEGAN: Nyssa, is that possible?
NYSSA: I don't know. It could be.
TEGAN: What do you think, Brigadier?
BRIGADIER: I've seen this happen twice. Different each time, but, well, this could well be the Doctor.
TEGAN: His features, how've they developed so quickly?
MAWDRYN: The atmosphere of the TARDIS has certain regenerative qualities, but my condition is unstable. We must return to the ship at once.
TEGAN: Why there?
MAWDRYN: It should have a laboratory. I need its equipment. Hurry!
NYSSA: We can't leave Turlough. He doesn't belong in this time zone.
MAWDRYN: Turlough?

[Transmat capsule]

(The young man is fiddling with the controls in vain.)

TURLOUGH: It should work.

[Obelisk hill]

DOCTOR: Quickly!

(The Brigadier follows the Doctor to the open transmat capsule.)

[Transmat capsule]

TURLOUGH: Of course! The transmitter.

(Turlough turns to see the Doctor.)

[TARDIS]

TEGAN: But if you're the Doctor, you should have transmatted to Earth in 1983.
MAWDRYN: Any escape from a warp ellipse can cause temporal anomalies.
NYSSA: It's true. That's what must have happened to the TARDIS.
MAWDRYN: But now I need your assistance to return the TARDIS to the ship.

[1983 Obelisk hill]

(The Doctor works on the transmitter.)

TURLOUGH: What will that do?
DOCTOR: Reflect the beam back off the ship.
TURLOUGH: So the warp ellipse will absorb the time differential?
DOCTOR: That's right.
TURLOUGH: But will it work?

[TARDIS]

MAWDRYN: Tegan, Nyssa, Brigadier. My old friends, please, help me.
BRIGADIER: Do we have any real choice? We must give him the benefit of the doubt in case he is the Doctor.

[Transmat capsule]

BRIGADIER: But will it work, Doctor?
DOCTOR: Always the optimist, Brigadier.
BRIGADIER: That's not an unreasonable question.
DOCTOR: By the way. Yours, I think.

(The Doctor tosses the crystal to Turlough.)

[TARDIS]

NYSSA: We're ready to leave, Brigadier.
BRIGADIER: And I'm coming with you.
TEGAN: Brigadier
BRIGADIER: No, don't argue.
NYSSA: As you wish.
MAWDRYN: Do not enter new coordinates. Activate sequential regression.

(Nyssa turns a dial, and a beeping starts up.)

TEGAN: Not another alarm?
NYSSA: I don't know. Doctor? I think it's the communication system.

[Transmat capsule]

DOCTOR: Turlough, would you check to see if the transmitter's functioning? Tegan and Nyssa can use the beam as a beacon. If all goes well, the TARDIS should reappear. Ah. Brigadier, quickly, think. Did you go into the TARDIS with Tegan and Nyssa?
BRIGADIER: I can't remember. Does it really matter?
DOCTOR: Of course it matters. Can you imagine what would happen if you walked out of the TARDIS in 1977 and met yourself in 1983?
BRIGADIER: Oh, that's ridiculous.
DOCTOR: It's not ridiculous, Brigadier, almost certainly catastrophic.
BRIGADIER: What, do you mean that I could be two people?
DOCTOR: Obviously. You'd exist twice over. And if the two of you met, you'd short out the time differential. Don't you see? The Blinovitch limitation effect? Oh dear. As Tegan would say, zap!

[Obelisk hill]

(The transmitter is starting to smoke.)

TURLOUGH: Doctor!

(Bang! goes the transmitter.)

DOCTOR: Oh no.

[TARDIS]

NYSSA: It's stopped.
MAWDRYN: Dematerialise.
TEGAN: Wait. If that sound came from the communication system, then maybe someone was trying to get in contact with us. Perhaps it was the Doctor.
MAWDRYN: I am the Doctor. Dematerialise immediately. Time is running out. We must leave this place at once.
TEGAN: No!

(Nyssa sets the TARDIS moving.)

[Transmat capsule]

BRIGADIER: If it's any use to you, Doctor, I recall now that I didn't board the TARDIS in 1977. I was standing near the transmitter and I remember it dematerialising.
DOCTOR: Thank you, Brigadier. The problem is now strictly academic. I cannot even return to the ship.
BRIGADIER: You're trapped on Earth?
DOCTOR: Unless I can assemble some equipment for tracking the TARDIS, and soon.
BRIGADIER: A sort of homing device?
DOCTOR: Indeed.
BRIGADIER: I have such an object. Tegan gave it to me.
DOCTOR: What did you say?
BRIGADIER: The homing device.
DOCTOR: Where?
BRIGADIER: You never know when something like that's going to come in useful.
DOCTOR: Brigadier, where is it?
BRIGADIER: Back at the hut.
DOCTOR: Come on. There isn't a moment to lose.

[TARDIS]

(The TARDIS materialises back inside the spaceship.)

MAWDRYN: The ship. You will all stay here in the TARDIS.
TEGAN: Wait. If you're in a regeneration crisis then you'll need all the help you can get.
MAWDRYN: No.
BRIGADIER: She's right, Doctor.
MAWDRYN: No, I must go into the ship alone. You do not understand the nature of the transmogrification, the unique restorative conditions of that vessel. The presence of other lifeforms would inhibit the reparation.
TEGAN: We've all seen the Doctor regenerate before, and it seems without the presence of other life forms, he could die.
MAWDRYN: Open the doors.
TEGAN: No. You're not going out into that ship alone. Either we go with you, or you stay here.
NYSSA: But Tegan
TEGAN: Look, he could reactivate the beam and the TARDIS could be stuck here forever.
NYSSA: But if he is the Doctor
TEGAN: I don't believe it.
MAWDRYN: Doors!
TEGAN: No!

(Mawdryn sinks to his knees.)

MAWDRYN: Hurry, you're destroying me.

[Brigadier's quarters]

(The Brigadier gets the homing device out of a box of circuit boards and wires.)

DOCTOR: It isn't working.
BRIGADIER: Well, can you repair it?
DOCTOR: Hopefully.

[TARDIS]

MAWDRYN: Spare me the endurance of endless time, the agony of perpetuity. For pity's sake, release me.
BRIGADIER: Do as he asks.
NYSSA: I agree.

(Nyssa opens the doors and Mawdryn stumbles out, the coat falling from his shoulders.)

TEGAN: I hope you know what you're doing.
NYSSA: We can't be certain he isn't the Doctor.
TEGAN: Can't we?

[Brigadier's quarters]

(Beep!)

DOCTOR: That's it.
TURLOUGH: Have you located the TARDIS?
DOCTOR: It must be on the ship. I'm a fool. I should have realised.
BRIGADIER: That thing Tegan saw inside the capsule. It must have been mutilated by the transmat process and couldn't survive the return journey.
TURLOUGH: So it's used your TARDIS?
DOCTOR: Yes. Come on, the capsule.
TURLOUGH: But there's no beam. The transmitter's been destroyed.
DOCTOR: You're forgetting this. The TARDIS is on board the ship, and this will home in on the TARDIS. Come on.
TURLOUGH: Coming? Sir.

[TARDIS]

BRIGADIER: Right, time for a recce. I think I'd better keep an eye on this character in case you're right about him, Tegan.
TEGAN: I'm coming with you.
BRIGADIER: You girls will stay here.
TEGAN: We girls are perfectly capable
BRIGADIER: You will both remain here in the TARDIS and that is an order, Miss Jovanka.

[Spaceship]

BRIGADIER: Good heavens.

[TARDIS]

(Nyssa and Tegan watch the Brigadier on the scanner.)

TEGAN: Chauvinist.

[Transmat capsule]

BRIGADIER: This is the third time today that I've yomped up that wretched hill.
DOCTOR: Good of you to come and see me off, Brigadier.
BRIGADIER: No, I'm not letting you out of my sight. You've raised too many questions that I want answering.
DOCTOR: The transmat could be dangerous.
BRIGADIER: I'm coming with you.
DOCTOR: If you insist.
TURLOUGH: And so am I.
BRIGADIER: Oh, don't be ridiculous, Turlough.
TURLOUGH: The Doctor needs my help. And besides, how do I explain to the Headmaster where you've gone?
DOCTOR: Turlough could be useful.
BRIGADIER: And what about the danger you implied?
DOCTOR: It still exists, but if you're so concerned about Turlough, set an example and stay behind.
BRIGADIER: Moral blackmail.

(The Doctor puts the homing device into the transmat controls, and the capsule vanishes. It reappears in the spaceship.)

BRIGADIER: How long will the journey take?
DOCTOR: Come on.

[Spaceship bridge]

BRIGADIER: It isn't possible. Such luxury.

[Spaceship]

(Meanwhile the early version of the Brigadier is still exploring. He walks down a set of stairs.)

BRIG '77: Doctor?

(Mawdryn crawls into the alcove with the busts on the wall.)

MAWDRYN: I, Mawdryn, have returned. It is time for the awakening. Help me.

(Turlough, the Doctor and the Brigadier walk down the stairs.)

BRIG '83: Doctor, we're supposed to be looking for the TARDIS. Your friends may be in danger.
DOCTOR: The creature will have left the TARDIS by now. He'll need his own life support systems.

(The Doctor runs back to a junction.)

DOCTOR: I don't remember that. Turlough, find the TARDIS and stay with Nyssa and Tegan. Brigadier, I want you to come with me.
BRIG '83: Are you sure?

(The Doctor walks down a short corridor to a blank wall, and presses a boss on a lintel. A door slides open.)

[Laboratory]

DOCTOR: A metamorphic symbiosis regenerator.
BRIG '83: Really.
DOCTOR: Used by Time Lords in cases of acute regenerative crises.
BRIG '83: Well, what's it doing here?
DOCTOR: It must have been stolen from Gallifrey.

[Spaceship]

MAWDRYN: I bring to the ship a TARDIS. The time of our ending is near. Help me.

(Mawdryn reaches for a bust, but collapses. Meanwhile, Turlough is having a one-sided conversation with the crystal.)

TURLOUGH: It's not my fault the Doctor was able to home in on the TARDIS. Can you hear me? There's not much I can do with the Brigadier about. Answer me!

[Laboratory]

DOCTOR: Someone on this ship has been trying to regenerate.
BRIG '83: The creature, the alien?
DOCTOR: It would explain the mutilation. Severe instability.
BRIG '83: Well, where is he now? Perhaps he didn't make it in time. Collapsed somewhere. May even be dead.
DOCTOR: Or undead, Brigadier.

(Mawdryn crawls out of the alcove, which goes dark again.)

BRIG '83: But why should this creature want to regenerate?
DOCTOR: Extend its life.
BRIG '83: But what for?
DOCTOR: I don't know, but you can be sure it's for no good reason. Ah. Brigadier, look at this.
BRIG '83: Hmm?
DOCTOR: Connections to the regenerator. Eight of them.
BRIG '83: So, there's more than one creature on board.
DOCTOR: Somewhere.

[Spaceship]

(Turlough has found the alcove. The eyes of a bust light up.)

GUARDIAN: While the Doctor is still alive, I am never far from you, Turlough.
TURLOUGH: I'm sorry. I wasn't to know the Doctor had a homing device.
GUARDIAN: Whimpering boy. You do not understand. Everything now acts towards the total humiliation of the Doctor. You have done well. Reach out your hand.
TURLOUGH: What?
GUARDIAN: There is nothing to fear. Reach out your hand.

(Turlough touches the bust and a door opens. Inside the room, seven aliens just like Mawdryn rest against misericords. They stir as he enters, so he runs out again.)

[Laboratory]

(The Doctor is examining the regenerator.)

BRIG '83: Shouldn't we get to the TARDIS?
DOCTOR: There have been some very cunning modifications.
BRIG '83: That all looks extremely dangerous.
DOCTOR: Oh, quite right. It could do very nasty things to a genuine Time Lord.
BRIG '77 [OC]: Doctor?
BRIG '83: Listen.

(The Brigadier leaves and the door closes behind him.)

DOCTOR: We should get back to the TARDIS, Brigadier.

[Spaceship]

(Brigadier 1983 narrowly misses meeting his younger self.)

BRIG '77: Doctor?

[Secret room]

MUTANT: Mawdryn has returned.
MUTANT 2: Does he bring hope of our ending?
MUTANT: Where is Mawdryn?

[Laboratory]

(The Brigadier returns.)

BRIG '83: Doctor, we must get on. Now where's he gone?

(A voice comes from the floor at the other side of the regenerator unit.)

MAWDRYN: Brigadier. Brigadier. Help me.
BRIG '83: Doctor?

[TARDIS]

TEGAN: I'm going after the Brigadier.
NYSSA: Is that wise?
TEGAN: I'm not in the army. I'm not taking orders from him.
NYSSA: But you could get lost out there.
TEGAN: Well, I'm prepared to take the risk. You can stay here if you want to. I'm going after the Doctor. The real Doctor.
DOCTOR: Right.
TEGAN: Doctor!
DOCTOR: Er, wait here.

[Laboratory]

(Mawdryn in propped up on a near-vertical couch, and talking the Brigadier through the procedure to use the regenerator.)

MAWDRYN: Increase the power. The energy repairs the depredations of the transmat capsule.
BRIG '83: You're not the Doctor at all.
MAWDRYN: I am Mawdryn.
BRIG '83: Where is the Doctor?
MAWDRYN: I don't know.
BRIG '83: You're lying. If you don't tell me, I shall disconnect the power.
MAWDRYN: No matter.
BRIG '83: I imagine it matters to you if you die.
MAWDRYN: Without the energy, only our shape will change. Our endless voyage will never cease. We cannot die.

[TARDIS]

(The Doctor returns from the interior.)

DOCTOR: Where's Turlough?
NYSSA: You brought that boy with you?
DOCTOR: And the Brigadier, but I've lost both of them.
TEGAN: What do you mean, you brought the Brigadier?
DOCTOR: You mean he's here with you as well?
TEGAN: As well?
DOCTOR: How could you be so stupid!
TEGAN: What?
NYSSA: He insisted on coming.
DOCTOR: He also insisted on coming with me.
NYSSA: Oh, no. What if they should meet?
DOCTOR: Precisely. Come on, we've got to find them.

[Spaceship]

(The Brigadier 1977 version hides as the mutants glide out of their and along a corridor. Meanwhile -)

DOCTOR: Better check the laboratory. Tegan, you stay here in case the Brigadier come past, in which case, stop him. Come on.

(The terrified Turlough runs into the TARDIS.)

[Laboratory]

BRIG '83: Doctor.
DOCTOR: Brigadier, thank goodness you're all right. One of you, anyway.
NYSSA: Doctor, that's him.
MAWDRYN: I am Mawdryn. Welcome to my ship, Time Lord.

[TARDIS]

(Turlough is trying switches on the console.)

GUARDIAN [on scanner]: You will not be able to operate the TARDIS.
TURLOUGH: I can work it if you show me how. Then the Doctor will be trapped and I can escape. Isn't that the agreement?
GUARDIAN [on scanner]: Do you think I have controlled you merely to prick the flesh of this presumptuous Gallifreyan?
TURLOUGH: What more do you want of me?
GUARDIAN [on scanner]: You will remain on the ship and witness the nemesis of the Doctor.

[Laboratory]

DOCTOR: It was you who stole the regenerator from Gallifrey.
MAWDRYN: Yes, Doctor, but time itself has punished us for that crime.
DOCTOR: And you modified the machine and created endless life for yourself.
MAWDRYN: Endless torment.
DOCTOR: Ah, you induced a perpetual mutation.
MAWDRYN: So horrible that the elders of our planet exiled us to this ship.
DOCTOR: How were you able to come to Earth?
MAWDRYN: Every seventy years the beacon guides us to within transmat distance of a planet, and using the mental energy of the other seven, one of our company may leave the ship to seek help, taking on the appearance of a native of that planet.
NYSSA: But what help can there be for you?
MAWDRYN: None, it seems. We remain in this pitiful state.
NYSSA: The TARDIS. You stabilised in the TARDIS.
MAWDRYN: That is true. The atmosphere of the TARDIS was suitable. But without those influences we degenerate.
NYSSA: But can never die.
MAWDRYN: It is the Time Lords' curse.
DOCTOR: It's the result of your own criminal ambition.
MAWDRYN: The Time Lords could have given us the missing element. They abandoned us!

(Tegan runs as the Mutants glide past.)

TEGAN: Doctor, there are others like him coming this way.
MAWDRYN: My brothers in exile.
TEGAN: I knew you weren't the Doctor.
BRIG '83: Look out!

(The Mutants glide in and take their places at the other couches.)

BRIG '83: Who are they?
DOCTOR: Fools who tried to turn themselves into Time Lords. It all went disastrously wrong.
MAWDRYN: It is eternal agony. That is why we long for death.
TEGAN: They're immortal?
DOCTOR: For what it's worth.
MAWDRYN: Help us.
DOCTOR: No.
MAWDRYN: Give us the energy of a Time Lord! Help us to die!
DOCTOR: I can't!
MAWDRYN: For pity's sake.
TEGAN: Doctor, why can't you help them?
DOCTOR: Don't you understand? If I did, it would be the end of me as a Time Lord.
Part Four

[Laboratory]

TEGAN: What do you mean?
DOCTOR: I can only regenerate twelve times. I have already done so four times.
TEGAN: So?
DOCTOR: Don't you see? Eight of them, eight of me.
TEGAN: They want your remaining regenerations?
DOCTOR: It's the only way to end their mutation.
NYSSA: Is that possible?
DOCTOR: With this equipment, yes.
BRIG '83: Let's get back to the TARDIS before they become hostile.
TEGAN: Come on, Doctor, we've got to get out of here.
MAWDRYN: We're scientists, not warriors. We have no weapons. The Doctor can only help us of his own free will.
TEGAN: What you want is murder eight times over.
MAWDRYN: No. What we desire is our own death.

[TARDIS]

GUARDIAN [on scanner]: Turlough, my plans are in hazard. This friend of the Doctor's
TURLOUGH: The Brigadier?
GUARDIAN [on scanner]: He is present on the ship in two aspects.
TURLOUGH: That isn't possible.
GUARDIAN [on scanner]: It is forbidden, but not impossible. He has travelled through time in the TARDIS.
TURLOUGH: But if the two aspects converged
GUARDIAN [on scanner]: The instability could destroy everything. You must find the Brigadier who travelled with the Doctor's companions.
TURLOUGH: Leave here?
GUARDIAN [on scanner]: You will obey me. The two Brigadiers must be kept apart.
TURLOUGH: What about those creatures?
GUARDIAN [on scanner]: They are harmless. They only threaten the Doctor.

[Laboratory]

MAWDRYN: We did not know that our experiments would bring endless mutation.
DOCTOR: You have the regenerator, the facilities of the laboratory. Continue your experiments, find how to reverse the process.
MAWDRYN: We have known for many years that the process is irreversible.
MUTANT: We have experimented for centuries.
MUTANT 2: We have tried to discover a remedy.
MUTANT: There is no remission.
MAWDRYN: Only you, as a Time Lord, can help us.

[Spaceship]

(Turlough leaves the TARDIS in search of Brig '77, who is still prowling the corridors of the spaceship, and finds him.)

TURLOUGH: Hello, Brigadier.
BRIG '77: Who the devil are you?

[Laboratory]

DOCTOR: I cannot do what you ask.
MAWDRYN: You cannot refuse.
DOCTOR: I must.
MAWDRYN: So be it, Doctor. Leave now, with your friends. But accept the consequences of your actions.
NYSSA: What does he mean?
DOCTOR: I don't know.
BRIG '83: Back to the TARDIS?

(Mawdryn smiles, and eases himself off the regeneration couch.)

[Spaceship]

BRIG '77: So you're Turlough? Yes, Tegan told me about you.
TURLOUGH: I've come to take you to the Doctor.
BRIG '77: The Doctor? You know where he is?
TURLOUGH: Of course. Come on.
BRIG '77: Not so fast. Keep in the shadows. We have some disagreeable fellow passengers.
TURLOUGH: They're harmless.
BRIG '77: That remains to be seen.

[Laboratory]

MUTANT: The Doctor was our only hope.
MUTANT 2: He must not be allowed to escape.
MAWDRYN: My friends, do not despair. The Doctor will soon return. And of his own free will.

[Spaceship]

DOCTOR: You see, Brigadier, thanks to your imperfect memory there is now a Lethbridge Stewart some six years your junior at loose in this ship.
BRIG '83: Good heavens. You mean that I did go with Nyssa and Tegan in the TARDIS in 1977?
TEGAN: And were we glad of the company.

[Spaceship - elsewhere]

BRIG '77: This Doctor, what does he look like?
TURLOUGH: Older than me, younger than you.
BRIG '77: No, I mean, is he normal?
TURLOUGH: Of course.

(They enter the alcove.)

BRIG '77: So, that deformed creature in the TARDIS was an imposter.
TURLOUGH: Exactly.

(Turlough calls into the secret chamber.)

[Secret chamber]

TURLOUGH: Doctor, the Brigadier's here.

(The Brigadier enters.)

BRIG '77: Doctor?

(Turlough closes the door behind the Brigadier.)

BRIG '77: Turlough, what are you up to?

[Spaceship]

BRIG '77 [OC]: Turlough!

[TARDIS]

TEGAN: No sign of Turlough.
BRIG '83: I never trusted that boy.
NYSSA: He must be here somewhere.
DOCTOR: Well, I hope so, because I've got to get the TARDIS away from here.
NYSSA: And separate the two Brigadiers.
BRIG '83: Ah, now, hang on a minute. I've been thinking about that.
DOCTOR: There isn't time to think, Brigadier.
BRIG '83: Doctor, we are talking about six years of my life.
DOCTOR: Well, you're perfectly all right in 1983. Obviously your 1977 self came to no physical harm.
BRIG '83: Well, maybe not, but I don't want to have spent a year or two in limbo on this ship.

(The scanner shows Turlough running through the corridor.)

NYSSA: Look.

(The Doctor opens the doors.)

DOCTOR: Stay here, all of you.

[Spaceship]

DOCTOR: Turlough, listen very carefully. We have a problem with the Brigadier.
TURLOUGH: What is it?
DOCTOR: The two time zones. The Brigadier did go with Tegan and Nyssa. There are now two Lethbridge Stewarts on this ship.
TURLOUGH: I understand.
DOCTOR: Now, I will take the Brigadier in the TARDIS back to 1983 Earth.
TURLOUGH: And me?
DOCTOR: You must find the other Brigadier and take him to the transmat capsule. You'll be quite safe, the mutants won't harm you.
TURLOUGH: But the transmat beam doesn't work.
DOCTOR: It will. The capsule is locked into the TARDIS' homing device. It will transmat to the centre of the TARDIS. I wired the device myself.
TURLOUGH: Of course.
DOCTOR: Now, when you arrive, whatever you do, stay in the capsule. Don't let the Brigadier out until I give you the word. Now, quickly.

(The Doctor goes back into the TARDIS. In the secret chamber, the Brigadier gets a penknife out on his key ring. Turlough hides from the mutants.)

[TARDIS]

NYSSA: Will the mutants really travel for the rest of time?
DOCTOR: I'm afraid so.
NYSSA: That's terrible.
DOCTOR: Sometimes you have to live with the consequences of your actions. Now, let's get away from here.

[Spaceship]

(The TARDIS dematerialises.)

MUTANT: The Time Lord has left us.
MUTANT 2: Can we be certain he will return?
MAWDRYN: He will return.

[TARDIS]

DOCTOR: It takes a remarkably cunning set of the coordinates to clear a warp ellipse.

(The girls look nauseous.)

TEGAN: Doctor?
DOCTOR: This is a temperamental old thing, but I'm getting remarkably good at sorting
NYSSA: Doctor, something's happening.
DOCTOR: Not at all. We're on course for the Brigadier's school. You see, there was a problem with
BRIG '83: Doctor!

(Nyssa and Tegan are aging rapidly.)

NYSSA: Doctor, do something.
BRIG '83: What on Earth is happening?
DOCTOR: I don't know.
BRIG '83: It's like Mawdryn in the laboratory.
DOCTOR: Mawdryn? That's it! They've been contaminated.
TEGAN: Doctor, do something.
DOCTOR: No, don't touch them. The transfiguration can be controlled.
NYSSA: Stop!
DOCTOR: Stop. That's it. Travelling through time is accelerating the degeneration.
BRIG '83: You've stopped the TARDIS?
DOCTOR: Well, more than that. We're going back to where we started. I just hope it induces a proportional remission.

(Brig '77 finds the boss on the lintel to open the door to the secret chamber, and leaves.)

BRIG '83: It's working.

(Tegan and Nyssa are back to normal as the TARDIS materialises in the spaceship.)

DOCTOR: Are you two all right?
NYSSA: I think so.
TEGAN: Doctor, what went wrong?
BRIG '83: Look at them out there. I'll bet they knew this was going to happen.

[Spaceship]

MUTANT: The Time Lord has returned, as you predicted.
MAWDRYN: The Doctor is not with us yet. He will not give up so easily.

[TARDIS]

DOCTOR: You were infected when you carried Mawdryn into the TARDIS. The journey to his ship would have made it worse.
TEGAN: Infected? You mean their mutation is a disease?
DOCTOR: Well, it shouldn't be. I can only assume their constant experimenting to correct their error brought about a viral side effect.
BRIG '83: Well, why haven't we got it?
DOCTOR: I don't know.
NYSSA: So we can't time travel.
TEGAN: We don't need to. All we need to do is get the TARDIS back to Earth.
DOCTOR: That won't work. I've got to programme a temporal deviation to escape the warp ellipse.
BRIG '83: Are we stuck on this ship?
DOCTOR: I wonder. If I reverse the polarity of the neutron flow

[Spaceship]

(Brig '77 arrives in time to see the TARDIS dematerialise.)

BRIG '77: So, you've stopped pretending to be the Doctor.
MAWDRYN: The Doctor is in the TARDIS.
BRIG '77: What?
MUTANT 2: This man also is in the TARDIS.
MUTANT: He is a deviant.
MUTANT 2: There has been temporal duplication.
MAWDRYN: The TARDIS will soon return. The imbalance could be cataclysmic. For your own safety you must return to the Earth at once.
BRIG '77: Without the TARDIS?
MAWDRYN: Quickly.

[TARDIS]

BRIG '83: So far so good.

(The girls start whimpering.)

DOCTOR: Oh, no.
BRIG '83: But nothing's happening.
DOCTOR: Oh yes, it is.

[Spaceship bridge]

MAWDRYN: You will return to Earth immediately in the transmat capsule.
BRIG '77: How the deuce do you expect me to
MAWDRYN: Get in.
BRIG '77: Look, if you think I'm trusting myself to this bauble
MAWDRYN: The capsule is programmed for Earth. Quickly.

[TARDIS]

(Nyssa and Tegan are now young children.)

NYSSA JR: It's no good, Doctor.
DOCTOR: We're travelling in the opposite direction out of the ellipse. It's having a reverse effect.
TEGAN JR: Stop! Stop!

(Mawdryn operates the transmat controls and send Brig '77 on his way, as the TARDIS materialises on the ship. Tegan and Nyssa are back to normal again. An alarm is beeping.)

DOCTOR: Someone's trying to operate the transmat capsule. Must be Turlough taking your other half to the centre of the TARDIS.
BRIG '83: Can the capsule do that?
DOCTOR: Only when the TARDIS is clear of the ship. Until that happens, the transmat can't take place. The capsule will return to its terminal.

(Which it does. Brig '77 is messing with the controls inside the capsule.)

DOCTOR: It's no good. I can't get clear of the ship without hurting Nyssa and Tegan.
NYSSA: What are we going to do?

[Secret chamber]

(Turlough runs in and carefully takes the glowing crystal from his trouser pocket.)

GUARDIAN [OC]: You have failed me!
TURLOUGH: No.
GUARDIAN [OC]: The Brigadier is still free.
TURLOUGH: That's not my fault.
GUARDIAN [OC]: Why did you not transport him in the capsule, as the Doctor instructed.
TURLOUGH: The Doctor? But I'm supposed to be working against him.
GUARDIAN [OC]: Imbecile! Why should you not profit by the Time Lord's cunning?
TURLOUGH: I'm sorry.
GUARDIAN [OC]: So near the annihilation of the Doctor and you risk all with your negligence and stupidity.
TURLOUGH: I can still keep the two Lethbridge Stewarts apart.
GUARDIAN [OC]: If you fail me again, I shall destroy you.

[TARDIS]

TEGAN: We can't stay in the TARDIS for ever.
BRIG '83: Well, Doctor?

(The Doctor opens the doors and goes outside.)

[Spaceship]

(Where Mawdryn and the mutants are still waiting.)

NYSSA: You knew that would happen.
MAWDRYN: Yes, Nyssa.
NYSSA: You infected us. You passed on the mutative pattern.
MAWDRYN: Yes, but not deliberately.
TEGAN: What happens to us now?
MAWDRYN: You will remain in the ship.
TEGAN: For the rest of our lives?
MAWDRYN: You're fortunate. Your journey will be short. Ours is without end.
BRIG '83: We are not leaving them on this ship.
MAWDRYN: Take them with you in the TARDIS and they will die.
BRIG '83: Are you telling me that with all the facilities on this ship, you can't come up with some sort of antidote?
MAWDRYN: We have no restorative for Tegan and Nyssa.
BRIG '83: Doctor, have you got any ideas? (silence) You said in the laboratory that the Doctor could help you through that machinery.
MAWDRYN: That is true, but only of his own free will.
BRIG '83: Well then, surely he can do the same for Nyssa and Tegan.
MAWDRYN: That is a question you must ask the Doctor.
BRIG '83: Well, Doctor?
TEGAN: Doctor?
NYSSA: Doctor?
DOCTOR: Take me to your laboratory.

[Spaceship]

(Brig '77 finds the TARDIS homing device in the transmat console and removes it. He goes out into the spaceship looking very pleased with himself.
Turlough hides as Mawdryn walks down the stairs with Brig '83, followed by the rest of the mutants with Tegan, Nyssa and the Doctor.)
MAWDRYN: The Doctor chose to involve himself. Soon he will be a Time Lord no longer. That is his reward for compassion.

[TARDIS]

BRIG '77: Doctor! Where is he?

[Laboratory]

(Nyssa and Tegan are hooked up to the regenerator along with the mutants.)

DOCTOR: You will activate the energy transfer, Brigadier. It will take several moments for the charge in the machine to build up. You can read off the countdown to the moment of exchange. Are you all right?
BRIG '83: (sadly) Yes.

(The Doctor links himself into the circle of people.)

MUTANT: Do not be afraid. When the moment comes, we will all share in the life force of the Doctor.
MUTANT 2: Our mutation will end.
MUTANT: You will no longer be contaminated.
NYSSA: And the Doctor won't be a Time Lord any more.

[Spaceship]

TURLOUGH: Brigadier? Brigadier!

[Laboratory]

MAWDRYN: My brothers in exile, we approach the ending.
DOCTOR: Activate, Brigadier, now.

(Brig '83 turns on the machine. Outside, Brig '77 hears the sound.)

[Spaceship]

(And so does Turlough.)

GUARDIAN [OC]: So near the supreme moment! The Brigadiers must not converge. Stop him, or I shall destroy you all!

[Laboratory]

BRIG '83: Twenty seconds. Nineteen.

[Spaceship]

TURLOUGH: Brigadier! Brigadier, come back!

(Brig '77 shakes off Turlough and opens the door to - )

[Laboratory]

BRIG '83: Thirteen, twelve, eleven
BRIG '77: Doctor, Tegan. What the devil?
DOCTOR: No, Brigadier, get out of here!

(Brig '77 stares at Brig '83.)

BRIG '77: What do you think you're doing? Who on Earth?
BRIG '83: I remember.

(The two Brigadiers raise their hands and touch. There is a blinding flash.)

[Spaceship]

(Turlough takes the Black Guardian's crystal from his pocket.)

TURLOUGH [OC]: It's cracked.

[Laboratory]

(The Doctor unhooks Nyssa from the regenerator. The mutants are all unconscious.)

DOCTOR: Are you all right?
NYSSA: I think so.

(He goes over to Tegan.)

TEGAN: What happened?
DOCTOR: A massive discharge of energy exactly synchronising with the moment of transfer.

(Brig '77 is lying on the floor.)

TEGAN: Is the Brigadier dead?
DOCTOR: I don't think so.
NYSSA: Doctor.

(Brig '83 is also on the floor, but starting to wake up.)

DOCTOR: It's all right, old friend.
BRIG '83: Oh, sorry about that, Headmaster. Touch of vertigo. It won't happen again. What the devil's been going on?
DOCTOR: Nyssa, I want you to take the Brigadier back to the TARDIS, right to the centre, and keep him there until I give you the all clear. You'll be quite safe.

(Nyssa and Brig '83 leave.)

TEGAN: This one must be all right. He belongs in 1977.

(The Doctor goes to the regeneration unit.)

DOCTOR: Amazing. The Brigadier's timing. A millisecond either way and
TEGAN: And what?
DOCTOR: At the moment of transfer, the power didn't come from me.
TEGAN: Where did it come from?
DOCTOR: Well, from the TARDIS, really. The two Brigadiers just shorted out the time differential.
TEGAN: You mean zap?
DOCTOR: Yes, that's right. Zap.
TEGAN: Can Nyssa and I still time travel?
DOCTOR: You're as good as new.
TEGAN: Can you still regenerate?
DOCTOR: I am a Time Lord.
TEGAN: Look at Mawdryn.
MAWDRYN: It is finished, Doctor. Can this be death?

(Mawdryn dies.)

TEGAN: They're all dead.
DOCTOR: They would have travelled for the rest of time, Tegan. Death was all they wanted. Come on, we must get the Brigadier back to 1977.
TEGAN: Before we go, Doctor, thank you. You were prepared to risk everything for us.
DOCTOR: Come on.

[TARDIS]

BRIG '83: Look, what's been going on?
NYSSA: The Doctor will explain later.

[Spaceship]

(The Doctor and Tegan are carrying Brig '77 between them.)

TEGAN: What's that noise?
DOCTOR: The ship is dying with the mutants.
TEGAN: It's come out of orbit?
DOCTOR: Yes. Hurry.

(Tegan opens the TARDIS door for him.)

[Obelisk hill]

RUNCIMAN: Brigadier?

(The TARDIS materialises.)

RUNCIMAN: Brigadier?

(Tegan and the Doctor carry Brig '77 out and lay him on the grass, then run back into the TARDIS.)

RUNCIMAN: Brigadier, what happened? I came as soon as I got your message.

(The TARDIS dematerialises. The Brigadier stares at it.)

RUNCIMAN: You'll be all right.

[TARDIS]

BRIG '83: My word, you've been making some changes in here, Doctor.
DOCTOR: One has to move with the times. How are you feeling?
BRIG '83: Haven't felt so well for, for at least six years.
DOCTOR: There we are, 1983. Back to school, Brigadier.

(When everyone has left, Turlough comes in from the interior and starts messing with the controls.)

[Obelisk hill]

DOCTOR: Goodbye.
BRIG '83: Goodbye, Doctor. If ever you're passing. Where's Turlough?
DOCTOR: Turlough. He left in the capsule.
NYSSA: He can't have done. If the Brigadier was still in the ship, he never used the transmat system.
TEGAN: The auto-destruct! We've got to get back to the ship. Come on!

[TARDIS]

TEGAN: Oh, Turlough.
NYSSA: You're safe.
TEGAN: We thought you were on Mawdryn's ship.
TURLOUGH: I'm not that easy to get rid of.
TEGAN: So it seems.
TURLOUGH: Doctor, may I join you?
DOCTOR: I think you already have.

(The Doctor and Turlough shake hands, while Tegan and Nyssa roll their eyes at each other and Mawdryn's ship goes KaBOOM!)

Transcript originally provided by Chrissie. Adapted by TARDIS.guide. The transcripts are for educational and entertainment purposes only. All other copyrights property of their respective holders.