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(A small rocky island sits on a vast ocean, ringed by a beach. Almost featureless, its most distinguishing feature is a tall pyramid that stands in the centre of the island. The TARDIS silently materialises on the beach.)


(The crew are gathered around the console. Although SUSAN and BARBARA have changed their clothes, IAN still wears the Chinese costume that he acquired during their previous adventure.)

IAN: Any radiation, Doctor?
DOCTOR: No, nothing to speak of. The counter's hardly reading anything. Shall we take a look?
BARBARA: Pity you don't have a colour television.
DOCTOR: Oh, but I have.
BARBARA: Where is it then?
DOCTOR: At the moment it's, er, temporarily hord-a-comba...

(His companions laugh. The DOCTOR switches on the scanner.)

BARBARA: Oh look, that's the sea, isn't it?

(The scanner shows a view of the beach and the still sea.)

SUSAN: Yes and sand! Grandfather, I wonder where we are?
IAN: Well, one things for sure - we’re not at Southend! (They laugh.)
SUSAN: Grandfather, can we go and have a look? Can we?
DOCTOR: Yes, yes, I don't think... I don't see why not. There's nothing... no danger about.
SUSAN: Good.
DOCTOR: Come on, lets go and have a look.

(SUSAN opens the doors. All except IAN turn to leave.)

IAN: (Unsure.) No.
DOCTOR: (Turning back.) What?
IAN: Well, I thought when you switched the scanner on… I thought I saw something move up there... Oh, probably just a shadow.
DOCTOR: Well let's go outside and have a look.

(They exit the TARDIS.)


(Outside four small transparent torpedo like objects travel silently through the water and slide onto the beach. The arrival of three of them is steady and sure but the fourth lands a small distance from its companions and its passage onto the beach is sluggish - as if it is encountering difficulties.)


(The time travellers walk out onto the beach, the DOCTOR carrying his walking stick. The rocks around them are unusually jagged. They look towards the sea.)

SUSAN: It is the sea. Why, it's beautiful!
IAN: Yes, absolutely calm. Not even a ripple.
BARBARA: It isn't frozen, is it?
DOCTOR: No, impossible in this temperature, besides, it's too warm.
SUSAN: Grandfather, do you think it's safe to go for a swim?
DOCTOR: Oh, no, no, no, not at the moment, child. However inviting that water looks, we don't know what sort of creatures may be lurking beneath its’ surface.

(They walk further down the beach. After they've gone, a figure emerges from behind a rock. It is humanoid, apparently dressed in a black wetsuit complete with flippers. It wears a helmet that completely obscures its face and from the front of which a black protuberance emerges, rather like a simple sort of aerial.)


(Further up the beach…)

BARBARA: It's so quiet!
IAN: Yes, it is. No birds or anything.
BARBARA: And there’s nothing growing.
DOCTOR: (Walking to them with some pebbles.) I say, what do you make of this, Chesterton? Fascinating, aren't they?
IAN: (IAN holds one and hurts his fingers on the sharp edges.) It's glass!
DOCTOR: Yes, yes, it is, isn’t it. Glass instead of sand. Intriguing. Intriguing, my boy! (He laughs.)
IAN: Do you think the sand turned into glass.
DOCTOR: Or was the glass put here deliberately, and if so, why?

(SUSAN is near to them and has found a rockpool.)

SUSAN: Mmm, there's a lovely pool over here! If I can't swim, at least I can paddle.

(She starts to take her shoes off placing them on the rock edge. BARBARA runs up and accidentally knocks one of them into the pool.)

BARBARA: Oh, oh, sorry Susan.
SUSAN: Never mind, I'll get it. You going to come in?
SUSAN: (About to put her feet in the water.) Now I’ll go…
IAN: (Shouts.) No, Susan! Don’t!

(In the pool, the shoe is dissolving into a cloud of bubbles. SUSAN hugs BARBARA in fright.)

BARBARA: Ian, what is it?
IAN: Must be some sort of acid.
BARBARA: But it was so fast. It just seemed to dissolve.
SUSAN: (Sobbing.) And I was going to paddle in it...
BARBARA: It's alright, Susan, it's alright. Look, you've got some more shoes back at the ship, haven't you?

(SUSAN nods.)

BARBARA: Well go and put them on. We'll wait here for you.
SUSAN: Alright.
IAN: Here, you'd better take my boots.

(He starts taking his boots off.)

SUSAN: I can't put those on, they're much too big for me.
BARBARA: Ah, come on, it's better than cutting your feet open on this glass.
IAN: Here.

(IAN hands his boots over and SUSAN starts to put them on with difficulty.)

SUSAN: Alright, better fill them up with sand, hadn’t I!
IAN: Alright?
IAN: Give you lovely corns, they will! (SUSAN laughs.)

(SUSAN heads off back to the TARDIS muttering something about the boots as she goes.)

BARBARA: (Realising.) Ian?
IAN: Mmm?
BARBARA: This is a tidal pool.
IAN: I agree. It rather ties up with the glass beach, doesn't it?
BARBARA: Then everything out there is acid too. A sea of acid!


(The web suited figure is examining the TARDIS and especially its lock when it is forced to hide as SUSAN approaches and enters the ship.)


(The DOCTOR has joined IAN and BARBARA.)

DOCTOR: Sea of acid, Mmm. Astonishing. You know, in all my travels I've never come across anything like this before. However, Susan wasn't harmed anyway.
BARBARA: No, she was a bit frightened at losing her shoes but she's gone back to the ship for another pair.
DOCTOR: (To IAN.) Yes, and if you'd had your shoes on, my boy, You could have lent her hers. You mustn't get sloppy in your habits, you know.

(IAN laughs not thinking it worth while to argue when suddenly the DOCTOR spots something behind him, further along the beach.)

DOCTOR: Good gracious!

(It is three of the transparent torpedo objects. They crouch down beside the nearest to them.)

BARBARA: It looks like a glass torpedo.
IAN: Or a one-man submarine. Well, it's certainly designed for going under the water.

(BARBARA wanders a short distance away.)

DOCTOR: Under acid, more likely.
IAN: Yes. I don't know whether it's occurred to you Doctor, but this means this place is inhabited.
DOCTOR: Oh yes, it has occurred to me. Let's see what it is, lets…

(He starts to try and undo the end of the first submarine.)

DOCTOR: Help me... Help me get this top off.
BARBARA: (Further down the beach.) Doctor!
BARBARA: There's another one over here... and there's something inside it!


(Meanwhile SUSAN has left the TARDIS. Out side she finds a trail of footprints which lead towards the centre of the island.)

SUSAN: Grandfather!

(There is no reply. Intrigued, she follows them, unaware that the web suited figure has come out of hiding behind a rock and is following her.)


(The others are crouched over the fourth submarine.)

DOCTOR: See that crack along there? That's where the acid must have seeped in.

(IAN has by now managed to open it.)

IAN: That's got it, now let's have a look at you.
DOCTOR: Yes, er, use that (He passes IAN his walking stick.)
IAN: Mmm? Oh, alright.

(IAN puts the stick into the submarine and uses the handle to grasp and pull out a wetsuit - similar to the one worn by the creature now following SUSAN.)

BARBARA: It's a protective suit!
DOCTOR: Yes and whatever it was wore it is similar to a human being. Hmm?
IAN: Yes but how did it get out? It seems to be perfectly intact.
BARBARA: I don't think it did get out. There's a tear in the material here.
IAN: You mean the acid got in? Poor devil.
DOCTOR: Yes well, I think we ought to go back to the ship and try and find Susan. She should have caught up with us by now. Come along!

(As they turn to go back, IAN suddenly spots the pyramid on the horizon.)

IAN: Look at that fantastic building!
DOCTOR: Good! Good! Now perhaps we might learn who it is uses these strange ships. Anyway, let's go back to the ship and find Susan. Later, perhaps, a little visiting, I think.

(He laughs)

IAN: Yes.

(They set off across the beach.)


(SUSAN has arrived at the base of the pyramid. After glancing up towards the apex she sets off along the passageway that surrounds it, unaware that around the next corner, the web suited figure is poised with a dagger.)


(BARBARA walks out of the TARDIS.)

BARBARA: She isn't inside anywhere.
DOCTOR: Oh, wretched child. Now where's she got to, I wonder?

(BARBARA points to the ground.)

BARBARA: Ian, there are your boots!

(IAN picks them up and starts to put them on.)

BARBARA: There are Susan's footprints in the sand here.
DOCTOR: Yes, sand here and glass on the beach. I'm beginning to think that sea of acid is a defence barrier.
IAN: Except against glass submarines, eh Doctor?
BARBARA: What you mean is, that all visitors are unwelcome?
DOCTOR: Yes, it would seem so.
IAN: We must find Susan. She may have gone to have a look at that building.
DOCTOR: Yes, yes.


(SUSAN approaches the corner of the pyramid, still unaware of the web suited figures’ presence. Without warning, the section of wall behind the figure rotates and it falls silently inside. Seconds later, SUSAN passes by without suspecting a thing.)


(The rest of the TARDIS crew have reached a different side of the pyramid. IAN and BARBARA look up in awe.)

IAN: Whew! It's enormous!
BARBARA: Look at the joins in the blocks, Ian.
IAN: Yes, no mortar! Must have been built with tremendous accuracy.
BARBARA: Yes, the Egyptians did the same thing. So did the Indians of Central and Southern America.
IAN: A precise distribution of certain weights. That's the key, isn't it?
BARBARA: Yes. It’s marvellous, isn't it?
IAN: Marvellous.
DOCTOR: Yes well, before you two get carried away, I think we'd better go and find Susan. Mmm?
BARBARA: Yes, you're quite right.
IAN: Well, for a start let's make a circle of this place.
DOCTOR: Excellent, now I suggest we go different ways and meet back at the furthermost point which is probably round the corner there somewhere, off you go, off you go now.

(They head off in different directions.)


(SUSAN leans back against the wall of the pyramid to tie her shoelace. Suddenly, it swivels round and, screaming, she falls into the pyramid.)


(IAN and BARBARA hear the scream.)

BARBARA: Did you hear that?
IAN: Yes, it was Susan, come on!


(The DOCTOR does not seem to have heard the scream. Stopping to rest he leans back against the wall of the pyramid and, like before, it rotates and he disappears inside.)


(IAN and BARBARA come to the next corner. IAN motions BARBARA to keep back as he peeps round the corner. He starts forward in surprise and steps into the open. BARBARA also looks round the corner. There is, of course, no one there.)

BARBARA: I could have sworn I heard her.
IAN: We certainly heard something. Well can't be sure it was Susan, of course.
BARBARA: Well I am sure.
IAN: Yes but where's the Doctor? Even if he'd been travelling at half speed he should have reached that far corner by now.


(Inside the pyramid, SUSAN continues walking along, nervously. Unseen by her, the web suited figure is hiding behind a pillar, still clutching the dagger. A man dressed in white monk-like robes with a hood appears at the end of the passageway from which SUSAN has just come. As SUSAN backs away the man retreats down the passageway. The web suited figure grabs SUSAN from behind and she screams. Suddenly it collapses with a dagger in its back. The robed man returns and starts walking towards SUSAN.)


(IAN and BARBARA are no nearer to finding their companions. BARBARA is sat on the floor.)

BARBARA: Well there's only one thing to do. That's another circuit of the walls.
IAN: I've just been all around, I can't find a door anywhere. (He walks round the corner.)
BARBARA: Well I suppose there's every chance she didn't come this way. She's probably back at the ship, waiting for us.

(There is no reply.)

BARBARA: I said, she's probably back at the ship, waiting for us.

(Still no reply.)

BARBARA: Ian? Ian!

(She peers round the corner to see that there is no one there.)


(BARBARA steps back and, once again, the wall revolves, forcing her into the pyramid. This time, however, a robed figure can be seen briefly in the opening.)


(IAN walks down the passageway that SUSAN was in earlier. He sees the stabbed creature on the floor and stops to examine it before proceeding.)


(The DOCTOR, SUSAN and BARBARA are talking in a cell.)

SUSAN: (Distressed.) ...dreadful. The wall just seemed to swallow me up. And then this…this man grabbed me and the next thing I knew he fell dead in front of me.
DOCTOR: Yes, yes, from what Susan has described he was wearing a suit similar to the one we found on the beach.
BARBARA: And are these the ones that live here?
DOCTOR: No, no. The man wearing the monk's habit lives in this building.
BARBARA: So the men from the glass submarines are intruders like us.
DOCTOR: Yes, with one difference, which is puzzling but relieving. They died, and we are only prisoners.
BARBARA: Well maybe we're to be killed too.
DOCTOR: Mmm, I shouldn't worry too much about that. That young schoolmaster friend of yours is very resourceful. Whilst he is free our chance of rescue is still good.
BARBARA: Well that's just it, Doctor. He isn't free. He was captured before I was.

(The DOCTOR'S face falls.)


(As the robed man walks down the corridor, another wet suited figure lunges at him. Running to his rescue, IAN tackles the creature and manages to evade the knife. The man is observing this from the other side of the passageway. As IAN forces the creature around and into an alcove, the stranger pulls a lever. The wall behind the creature falls away and it topples backwards, with a scream, falling into a huge pool of acid down below. The wall slides back into place.)

MAN: (Gasping for breath.) Why do you protect me?
IAN: Are you a prisoner here?
MAN: In a way, I…can never leave here but in a way, this is my home.
IAN: Where are my friends?
MAN: Safe. I saw your machine materialise. Until I knew otherwise, I had to treat you as potential enemies. The Voord were trying to penetrate the walls.
IAN: The Voord?
MAN: The man you just saved me from was a Voord. It is many years since their last assault but now they have returned and if they continue to come, they're bound to succeed eventually.
IAN: I should've thought this place was impregnable. How many of you defend it?
MAN: How many? (Sighs.) I am alone. But please…let us release your companions and then I…I'll try to explain.
IAN: Good idea.

(They turn a corner and pass through a doorway, which the man shuts behind him, unaware that they are being trailed by another VOORD.)


(A large glowing machine dominates the room. It is pentagonal and appears to be made of a transparent material with struts reaching to the ceiling, floor and walls. The man who is called ARBITAN and the TARDIS crew are talking.)

DOCTOR: Yes, yes, I want to know more about this planet. Your technology, you say, reached its peak over two thousand years ago?
ARBITAN: Yes and all our knowledge culminated in the manufacture of this.

(He gestures towards the machine.)

ARBITAN: At the time it was called the Conscience of Marinus. Marinus, that is the name of our planet. At first this machine was simply a judge and jury that was never wrong and unfair, and then we added to it, improved on it, made it more and more sophisticated until finally it became possible to radiate its power and influence the minds of men throughout the planet. They no longer had to decide what was wrong or right. The machine decided for them.
DOCTOR: I see, then in that case it was possible to eliminate evil from the minds of men for all time.
ARBITAN: That is exactly what happened. Marinus was unique in the Universe. Robbery, fear, hate, violence were unknown among us. Yes, yes. For seven centuries we prospered and then a man named Yartek found a means of overcoming the power of the machine.


(They are unaware that a VOORD is crouched by the door, eavesdropping on their conversation.)

ARBITAN: (OOV.) He and his followers, the Voords, were able to rob, exploit, kill, cheat. Our people...


ARBITAN: ...could not resist because violence is alien to them.
IAN: But surely by this time this machine had become a great danger to you. If it'd fallen into the hands of the Voords they could've controlled Marinus, why didn't you destroy it?
ARBITAN: We always hoped to find a way of modifying it and making it again irresistible, so instead of destroying it we removed the five key micro-circuits.
IAN: What did you do with them?
ARBITAN: One of them I kept. There it is.

(He points to a small transparent slim circuit board inside a similar shaped cavity in the machine.)

ARBITAN: The other four were taken and put in places of safety all over Marinus. Only I know where they are. And now the time has come when they must be recovered!
BARBARA: Well, why don't you simply make new keys?
ARBITAN: The keys are very simple but the micro-circuits inside are very complicated. A permutation of numbers and signals that would take a thousand years to unravel. And besides, since the keys were hidden, I have worked on this machine and modified it so that when they're replaced...
DOCTOR: (Interrupting.) …when they're replaced it would mean that your machine is irresistible and you could overcome and control the Voords again?
IAN: Surely there must be someone you can send for these keys?
ARBITAN: (Thoughtful.) Through the years all my friends, all my followers have gone. They have never returned. Last year I sent my daughter. She has not come back. All I have now to comfort me is the…distant echo of her voice…the imagined sound of her footsteps. But now your coming has brought new hope…oh yes…yes…

(He points at the travellers.)

ARBITAN: You must find the keys for me!

(They look at each other in shock.)


(IAN and BARBARA approach the TARDIS.)

BARBARA: Ian, wait a minute.
IAN: Mmm?
BARBARA: The Doctor's miles behind.
IAN: Oh.
BARBARA: I don't know about you but I felt terrible leaving that old man. We seemed to be his last hope.
IAN: Yes, I wish there had been something we could have done for him.

(SUSAN and the DOCTOR catch up with them.)

SUSAN: Oh, come on, grandfather!
DOCTOR: I'm coming, child, don't rush, I'm coming. (To IAN and BARBARA.) Well, well, don't just stand there, come along, come along, keeping me waiting.

(The others laugh and follow. Just in front of the TARDIS he suddenly stops in his tracks. There is a strange humming noise.)

DOCTOR: (Mutters something then.) What...

(He seems to press solid air. So does IAN as he comes forward. The two women join them.)

BARBARA: What is it?

(She feels the air in front of her.)

IAN: It's some sort of invisible barrier! What do you make of it, Doctor?
DOCTOR: I don't know, I don't know, there's no substance here. (To SUSAN.) Have a look round the side, child, go along.

(SUSAN traces it around the TARDIS.)

BARBARA: It's like an invisible wall.
DOCTOR: Is it a circular barrier?
SUSAN: It's goes all the way round. There aren't any corners to it.
DOCTOR: No, of course, there wouldn't be. No, the molecules would be at their weakest.

(He gives out a triumphant laugh.)

DOCTOR: It's fascinating, Chesterton. Yes, I've got it, I've got it! Do you know, I think a force barrier has been thrown up around the ship!

(Suddenly, ARBITAN'S voice echoes around them.)

ARBITAN: (OOV.) I am sorry you have forced me into keeping you from your ship. But your refusal to help me left me no alternative!
IAN: (Shouting.) Arbitan! Where are you?
ARBITAN: (OOV.) That is not important. If you help me find the keys of Marinus I will let you have free access to your machine... when you have delivered all the keys to me. If not, you will stay on the island without food or water. The choice is yours.
IAN: (Shouting.) Choice? What choice?

(There is no reply.)


(ARBITAN is showing IAN and BARBARA a map of Marinus.)

IAN: Well, at least we know the rough location of the keys. Now all we have to do is get them.
ARBITAN: As soon as you've started your voyage I will release the force field. Your ship will be available to you when you return.
BARBARA: If we return.
DOCTOR: (Angrily.) I know we have no choice but this whole affair is, is outrageous! Blackmail! Pure and simply blackmail!
IAN: Oh, Doctor, don’t let's go through all that again. Let's just get on with the job.
ARBITAN: Perhaps you will bring me news of my daughter. I miss her, yes, I miss her.
DOCTOR: And another thing. If you think I'm going to travel across that acid sea in one of these primitive mer…er, submersibles you're very much mistaken.
ARBITAN: To think of asking you to travel in such an absurd way!
ARBITAN: No, I am going to give you a device which will enable you to move from place to place.
DOCTOR: (Uninterested.) Oh, Really.
ARBITAN: The principle is much the same as that of your ship...

(He hands BARBARA a device. It looks like a watch with a dial where the face should be.)

ARBITAN: Place that around your wrist, please. ...that you have told me about. Except this will enable you to cross space, not time.

(ARBITAN hands out the travel dials.)

IAN: What, this little thing?
DOCTOR: Oh, don't be ridiculous, my boy, this is a perfectly acceptable method of travel. Very compact and very neat, sir, if I may say, yes!
ARBITAN: They are all programmed to the same destination. You have only to twist the dial…once.
BARBARA: Like this?

(She twists the dial and disappears.)

SUSAN: (Alarmed.) Barbara!

(IAN runs up to the spot where she was standing , followed by the DOCTOR and SUSAN.)

IAN: What...? (To ARBITAN.) What have you done to Barbara?
ARBITAN: You must not waste time, you must follow her quickly! One final word, if, when you return, you find the Voord have taken this building, do not let them get the keys! You understand? Destroy them! Now, now, twist the dials.

(The rest of the TARDIS crew do so and they also disappear.)

ARBITAN: For the sake of all my people, I hope you succeed.

(He moves over to the machine. A VOORD silently crosses the room. ARBITAN turns around only for the VOORD to stab him in the back. He cries out and collapses.)


(The DOCTOR, SUSAN and IAN fade into view in front of what appears to be an elaborate latticed wall.)

DOCTOR: Ha ha, oh, how exhilarating! (The DOCTOR and IAN laugh.)
SUSAN: Yes but where's Barbara? She should be here by now. (Calls.) Barbara! Barbara!

(IAN spots something on the ground.)

IAN: Oh, it's Barbara's travel dial.

(He picks it up. His face suddenly grows alarmed.)

IAN: Look! There's blood on it!

Next episode

Dr. Who

Ian Chesterton

Barbara Wright

Susan Foreman



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