Doctor Who (1963–1989): Season 18, Episode 12 - Full Circle: Part Four - full transcript

Marshmen invade the Terradonian ship thanks to Romana, who seems to be in communion with them. While the ship's inhabitants flee for their lives, the Doctor discovers a crucial fact why these humanoids can never return to the planet Terradon.

What's that?

It's the other half of my waistcoat.
What's that?

- Image translator.
- What?

It's broken.

Right. No more pictures
of Gallifrey, then. Come on.

Security alert.

Number one emergency hatch
has been opened.

Number one emergency hatch
has been opened.

Security alert.

Number two emergency hatch
has been opened.


Let's go.

You know, she could be anywhere.

Must be a better way of doing it
than this.

We've come full circle.

You know what I think?

- That's what the Decider said.
- Decider?

- In the marsh. His last words.
- Really? What did he say?

- Exactly, what did he say?
- "Tell Dexeter we've come full circle."

"Tell Dexeter we've come full circle."
How's your knee, by the way?

That was hours ago.

That was quick.

Old people take a bit longer,
of course. Sometimes a whole day.

Really? Rapid cellular adaptation,
that settles it.

- Settles what?
- We're going back to the science unit.

Come on.

All citizens remain
in their quarters.

All citizens remain in their quarters.
The Starliner has been boarded by...

- Varsh.
- Marshmen.

- We've got to go back for Tylos.
- No, no, no. You're not going anywhere.

- Take cover in the science unit. Go.
- But we must...

In the science unit.

How did they get in?
The entrances are sealed.

That's right.
What if the Doctor's betrayed us?

I don't think so. He's already
demonstrated his great wisdom.

He's not a man to side with chaos.

Nevertheless, chaos surrounds us.

What are we to do?

Yes, what are we to do?

Well, Login, you're a Decider now.

What are we to do?




We're not helping much in here.

Look, you've got alien protein
in your brain tissue.

I haven't had time to analyse it yet,

but the effects are probably
only temporary.

Please, please, don't do that. Look,
this is your problem. Think about it.

Psychopathology, huh? Why are you
doing this? Think about it. Look.

Look, K9. You remember K9
and the Tardis.

Tardis. Stay by the Tardis.

Stay by the Tardis.

Stay by the Tardis.

It might be possible to close
this substructure.

No, it seems that the marsh creatures
are already inside the main hull.

- The bulkheads, then?
- One recourse, certainly.

Nefred, Garif, we must close
these bulkheads and these,

and we must gather the citizens
in here at once.

Yes, I see the plan
has some merit in it, but...

And we must do it quickly.

We must certainly respond to this crisis
on a real-time basis, Decider Login,

- but appropriately.
- Decider Nefred is right, Decider Login.

I have been consulting the histories
of our relationship with the marshmen.

While a single defence
response has a certain appeal,

we must also consider
the long-term consequences.

- It is not a defensive response.
- We need a holistic approach, I think.

I wonder if you've had time
to consult this manual

on the peripheral unit power supplies.

The Doctor told us to stay in there.

- But we're not doing anything.
- What can we do?

Come on.

"That the marsh creatures,
though they rarely speak,

"are the possessors of intellect."

Furthermore, they have amazing powers
of adapting to new situations.

Yes, their emergence from the marsh,
for instance.

- Breathing air through their gills.
- So you can see the difficulty.

So you're suggesting that we do nothing?

Well, nothing too precipitate.

Whatever measures we do,
they will adjust to.

And that is your conclusion from
all this knowledge? Do nothing.

- This knowledge and more.
The assistant Deciders concur?

They do.

Hasty action will only add to
the general sense of panic.


- I thought I told you three to stay put.
- We wanted to help.

- Doctor, where's Tylos?
- He's dead.


Lock that door and barricade it.

Dexeter's been doing DNA analysis.

- Adric.
- It's what you wanted, isn't it?

- For the Tardis.
- But it's other people's property.

Do you think it's right to go around
taking other people's property?


Well, if it works on the Tardis,
it would definitely prove

- we're in E-Space.
- E-Space?

Yes, the Exo Space-Time Continuum,
outside our own universe.

I suspect that what we came through...

Look, do you mind if we do
one thing at a time?

Good. Now for a short course
of cytogenetics.

Close the emergency hatch.

See that the bulkheads are each closed
on each end of this section.

So you've got spider tissue
and the marsh creature.

And here's the first slide
of batch three.

Thank you.

Oh. Tsk, tsk.

Alas, poor Dexeter.

Reduced to a tangle
of stained chromosomes.

It's ready, Doctor.

Yes. Well, that should put
Romana to rights.

Login, Garif,

we have procrastinated too long.

If you survive this...


Seek out the Doctor.

He can teach you to fly the Starliner.

It is my wish that you all leave


And return to Terradon?

No, we cannot return to Terradon.

- But if the Doctor shows us how?
- We cannot return.


Because we have never

been there.

Decider Nefred, what are we to do?
Tell us. Tell us what to do.

He's already told us what to do.

Garif, we must find the Doctor.

You understand? Avoid all contact.

Avoid all contact.

Adric. Adric, the serum.

It's the oxygen. It's too rich.
They can't adapt quickly enough.

- Doctor, look out.
- Hmm?

Quick, the serum.

Where's the Doctor?

Follow us.

- Good.
- Suppose it doesn't work?

If it doesn't work, she's dead.

How long's it supposed to have been
since the Starliner crashed?

- Forty generations.
- Forty generations.

That's a good round figure.
Can't be right, though.

- Why not?
- Well, evolution goes in quantum leaps,

but it doesn't go that fast.

What are you doing?

Karyotype comparisons.

Yes. Definitely morphological
similar karyotypes.

The inversions in
bands eight to ten might be significant.

I need to establish how long
the evolutionary process has taken.

From spiders to marsh creatures?

From spiders to marsh creatures
and beyond.

- You could try gel electrophoresis.
- That's a good idea.


Don't touch him.

Look out.

- We're all right, go on.
- We'll find the Doctor, come on.

My cylinder is running out.

Leave this to me.
Go and get some more oxygen.

- I can't leave you on your own.
- Adric, don't argue.

Forty generations?
More like 4,000 generations.

Since the Starliner crashed?

Yes. The Deciders procrastinated
more than we'd thought.

- Can I see?
- Hmm.

How can you tell all that
from the marsh creature cells?

That's not the marsh creature.
That's Dexeter.


That's the marsh creature.

And that's the spider.

- The same cells.

- Varsh is trapped.
- What?



Is he dead? Poor Varsh.

- Have you any more oxygen?
- As much as you want.

- We have an electrolytic power system.
- You actually make the stuff?

- Yes.
- Splendid.

Enough to flood the whole Starliner?

- Well, I'll see what I can do.
- Good.

He saved our lives.

You'd better keep this for him.

Oxygen supply to
all areas. Oxygen supply to all areas.

Oxygen supply to all areas.

Oxygen supply to all areas.

We've got to kill them.

No. No, I think we should let them go.



Emergency hatch one open.

They're adapting quickly.

- They'll learn to breathe the air.

They might break the ship
and wipe out the crew.

Still, the manuals in
the Great Book Room will show them

- how to put it all together again.
- They could learn to read?

Oh, yes. Just as they did
40,000 generations ago.

They're your ancestors.

Nefred's dying words.

That's why we can't return to Terradon.

- It's horrible.
- Oh, I don't think so.

We're all basically primeval slime
with ideas above its station.

How can you compare us to those...

Those things?

Yes, I see what you mean. I suppose
they are adaptive, intelligent.

Login, shut the door.

They've gone.

- But how long for?
- What?

- They've learned to get out.
- Well, quite.

Will they learn to come in?

So the first marshmen
came to resemble

the original crew of the Starliner?

Yes. The environment of the
creatures most fitted to survive in it.

But we're not Terradonians.

You're not Terradonians.
You're not marshmen either,

- which is what they seem to resent.
- I'm afraid they'll return.

- Lf they re-enter the ship...
- We must do what Nefred said.

Doctor, you must fly the Starliner.
You must fly us out of here.

What? You mean fly you to Terradon?

- Or any other suitable planet.
- Well, certainly. This is a colony ship.

We can program it to find them.

If they stay here, generations
of evolution may be wiped out.

Please, Doctor, it's our whole future.

Stabiliser. Power. Fuel.

- The system files, Doctor.
- Good.

And this is the flight manual. I've
heard of it, but I've never seen it.

The pages referring to takeoff
were damaged in the crash.

Shh. Ready? Ready?

Thrusters one, two, three, four,
and five.

- Ground hold disengage.
- All right.

- Then it's just ignition.
- Which is that button there, gentlemen.

- The manual is readable from there on.
- Have a good flight, gentlemen.

But, Doctor.

You don't want us to take off
on our own?

Doctor, come back.

The green button, gentlemen.

Such a momentous decision.

We must do what Nefred said.

I see his point,
but on the other hand...

Garif, we must live up to our names.

- We must make this decision together.
- Yes, of course.

But you will agree,
it does require some thought.

They asked me to stay on, you know,
be a Decider.

- You, a Decider?
- Yes. I decided not to.

Doctor, what did happen
while I was unconscious?

Oh, Adric and I were too busy
to think about you.


- Adric's left us a present.
- Really?

An image translator. Loot.
He stole that...

Still, it might come in useful.

- It works.
- Yes, unfortunately.

- Negative coordinates.
- Yes, that settles it.

We're out of our own time and space,

- Exo-Space?
- Yes. That thing we came through

was a Charged Vacuum Embointment.

- A CVE.
- Hmm.

One of the rarest Space-Time events
in the universe.

Doctor, look.
The Starliner is taking off.

Well, they've made a decision.

And we're trapped.

Unless we can find another CVE.