OFFICE

A symmetrical wood-panelled room. Over the mantelpiece hangs a 1661 Rembrandt self-portrait. The clock on it ticks away as shuffling footsteps approach, then Nardole enters through the left hand door from our point of view, followed by a sulky girl of dark complexion with a touch of the River Song about her. Nardole's arm squeaks mechanically as he gestures for her to sit in front of the desk, then a bolt falls off. The girl looks at Nardole. He smiles and kicks it behind him, then backs out and closes the door. The girl runs to investigate the Police Telephone Box sitting in the corner of the room by a window. It has an 'Out of Order' sign hanging on the door. She then scuffles to the desk which has photographs of Susan Foreman and Melody Pond aka River Song on it. The clock chimes. Bill is reaching for the pot that contains not pencils or pens, but sonic screwdrivers, when suddenly the peace is ripped apart by an electric guitar playing Beethoven's Fifth.

EN: May be Saint Cedd's College Cambridge.

BILL: Ahem!

The guitar stops, then rock star Doctor puts his head out of the right hand door, then back in again. There is the whirr of a sonic screwdriver and a bit of amplifier feedback, then he comes out into the room.

DOCTOR: Potts?

BILL: Yeah.

DOCTOR: Bill Potts.

BILL: You wanted to see me.

DOCTOR: Er, you're not a student at this university.

BILL: Nah, I work in the canteen.

DOCTOR: Yeah, but you come to my lectures.

BILL: Surprised. No, I don't. I never do that.
DOCTOR: I've seen you.

BILL: Love your lectures. They're totally awesome.

DOCTOR: Why'd you come to my lectures when you're not a student?

BILL: Okay, so my first day here, in the canteen, I was on chips. There was this girl. Student. Beautiful. Like a model, only with talking and thinking. She looked at you and you perved. Every time, automatic, like physics. Eye contact, perversion. So I gave her extra chips. Every time, extra chips. Like a reward for all the perversion. Every day, got myself on chips, rewarded her. Then finally, finally, she looked at me, like she'd noticed, actually noticed, all the extra chips. Do you know what I realised? She was fat. I'd fatted her. But that's life, innit? Beauty or chips. I like chips.
So did she. So that's okay.

DOCTOR: And how does that in any way explain why you keep coming to my lectures?

BILL: Yeah, it doesn't really, does it? I was hoping something would develop. What's that? A police telephone box?

DOCTOR: Yeah.

BILL: Did you build it from a kit?

DOCTOR: No, it came like that.

BILL: Then how did you get it in here? The door's too small and so are the windows.

DOCTOR: I had the window and a part of the wall taken out and it was lifted in.

BILL: What, with a crane?

DOCTOR: Yeah, with a crane. It's heavier than it looks. Why do you keep coming to my lectures?
BILL: Because I like them. Everybody likes them. They're amazing. Why me?

DOCTOR: Why you what?

BILL: Well, plenty of people come to your lectures that aren't supposed to. Why pick on me?

DOCTOR: Well, I noticed you.

BILL: Yeah, but why?

DOCTOR: Well, most people when don' t understand something, they frown. You smile.

BILL: I'll tell you what I don't understand. You've been lecturing here for a long time. Like, fifty years, some people say. Nabeela in the office says over seventy.

DOCTOR: Yeah, and you're thinking, 'Well, he doesn't look old enough'.

Bill cuts him off.

BILL: No. I'm wondering what you're supposed to be lecturing on. It's like the university let you do whatever you like. One time, you were going to give a lecture on quantum physics. You talked about poetry.

DOCTOR: Poetry, physics, same thing.

BILL: How is it the same?

DOCTOR: Because of the rhymes. What are you doing at this university?
BILL: I always wanted to come here.

DOCTOR: Yeah, to serve chips?

Bill is saddened.

BILL: So anyway, am I nearly done?

DOCTOR: Do you want to be?

BILL: See ya.

DOCTOR: You ever get less than a first, then it's over.

BILL: You what?

DOCTOR: A first. Every time, or I stop immediately.

BILL: Stop what?

DOCTOR: Being your personal tutor.

BILL: But I'm not a student. I'm not part of the university. I never even applied.

DOCTOR: We'll sort all that out later.

BILL: You kinda have to sort that out earlier.

DOCTOR: Leave it with me. I'm assuming that it's a yes.

BILL: Yes.

DOCTOR: I'll see you at 6 pm every weekday. I don't care who's dying, never, ever be late. I'm very particular about time.

BILL: Oh, em. People just call you the Doctor? What do I call you?

DOCTOR: The Doctor.

BILL: But Doctor's not a name. I can't just call you Doctor. Doctor what?

SERIES 10 INTRO

LECTURE HALL

Intercut with Bill waking up, cooking chips in the canteen, and serving big portions to a well-built woman and winking at her.

DOCTOR: Time! Time doesn't pass. The passage of time is an illusion, and life is the magician. Because life only lets you see one day at a time. You remember being alive yesterday, you hope you're going to be alive tomorrow, so it feels like you're travelling from one to the other. But nobody's moving anywhere. Movies don't really move.

Six o'clock.

DOCTOR: They're just pictures, lots and lots of pictures. All of them still, none of them moving. Just frozen moments.

Bill is at the door, ready to knock. A series of pictures of Bill is on screen while the doctor talks.

PRODUCED BY PETER BENNET

DOCTOR: But if you experience those pictures one after the other, then everything comes alive.

DOCTOR'S OFFICE

The door swings open.

BILL: Am I on time?

DOCTOR: That's a very big question.

He throws her a book in slow motion.

BILL'S HOME

Bill looking through graded papers - The Cosmic Far Ultraviolet Background 97%, Quantum Statistics of Light 88%, Laser cooling of ions: atomic clocks and quantum jumps 92%

BILL: You know you're my foster mum? He's like my foster tutor.

MOIRA: Am I going to have to break every bone in his body?

BILL: It's not like that.

MOIRA: You need to keep your eye on men.

BILL: sotto Men aren't where I keep my eye, actually.

LECTURE HALL

DOCTOR: Imagine if time all happened at once. Every moment of your life laid out around you, like a city. Streets full of buildings made of days. The day you were born, the day you die. The day you fall in love, the day that love ends. A whole city built from triumph and heartbreak and boredom and laughter and cutting your toenails. It's the best place you will ever be.

BAR

Bill laughing, then her eyes meet those of another woman across a crowded bar.

DOCTOR OC: Time is a structure relative to ourselves.

BILL: I'll get them in.

DOCTOR: OC: Time is the space made by our lives where we stand together, forever.

Lecture hall

DOCTOR: Time And Relative Dimension In Space. It means life.

CANTEEN

BILL: Just chips, yeah?

WOMAN: Please.

In the quadrangle, Bill watches the Doctor and Nardole scurry around the corner of the building, Nardole turning the wrong way originally. She follows them to a cellar door which opens for her.

CELLAR

NARDOLE OC: So you're tutoring her, then?

DOCTOR OC: Yes, I am.

NARDOLE OC: Why?

DOCTOR OC: Why not?

NARDOLE OC: You're not supposed to get involved. What are you teaching her, anyway?

DOCTOR OC: Everything.

NARDOLE VOICE Well, how can you teach anyone everything?

DOCTOR OC: Because everything rhymes. Links apple and alpha, synchronous and diverging. Descending multiples.

Beep.

NARDOLE OC: Yeah, you want to turn that.

More beeps.

NARDOLE OC: You want to rotate it.

Bill slowly sneaks from behind. The sonic whirrs.
She hides knocking over some metal. The Doctor and
Nardole look concerned. They are by a huge metal vault door. The name board of the Marie Celeste is down here too.

DOCTOR: The door upstairs, how did you set the security?

NARDOLE: Friends only.

Bill starts to sneak away.

NARDOLE OC: So turn it, and then it'll

DOCTOR OC: I'm turning it, aren't I?

QUADRANGE

Bill comes across the woman from the bar sitting on a bench.

Intercut with memory of them looking at each other in bar.

BILL: You okay?

HEATHER: Yeah, I'm fine.

BILL: Sorry, can I ask? What's that in your eye?

HEATHER: It's just a defect in the iris.

BILL: Looks like a star.

HEATHER: Well, it's a defect.

BILL: At least it's a defect that looks like a star.

HEATHER: I'm getting it fixed.

BILL: Okay. Sorry, none of my business, but are you freaking out
about something?

HEATHER: Please. But, you can say no. Would you come with me? Can I show you something?

BILL: God, yes!

PEDESTRIAN WALKWAY

BILL: God, I love this place, don't you?

HEATHER: I hate it.

BILL: Why?

HEATHER: I don't know. I just do. Everywhere I go I just want to leave.

BILL: Can I come too?

HEATHER: Maybe.


SERVICE AREA

They come to a concrete service area between large buildings, with temporary fencing and storage units.

HEATHER: There's a puddle over there, but it hasn't rained for a week.

BILL: Yeah, but, well, you know, half the students here are blokes.

HEATHER: Go and look in it.

BILL: You want me to look in a puddle?

HEATHER: Please.

Bill goes over to the puddle.

BILL: Okay, I'm looking. What am I looking at?

HEATHER: Your reflection.

BILL: Yep. There it is.

HEATHER: Do you see what's wrong with it?

Yes, her hair parting is on the wrong side of the reflection.

BILL: My name's Bill, by the way.

HEATHER: I'm Heather. Can you see what's wrong?

BILL: Nothing. It just looks like me. Oh! What is that? That's me, that's my face, but It's wrong.

Heather is walking away.

BILL: Hey!

HEATHER: Sorry. Some other time.

BILL: Promise?

ALIEN VOICE OC: Pilot is located. Link is established.

The view from the puddle is streaming down into somewhere, then it freezes over.

OFFICE

We discover that we are supposed to be at St Luke's University Bristol. Snow has fallen. Somewhere a choir sings Jingle Bells. Bill is carrying a long round present for her tutor.

DOCTOR: It's a rug. Haven't got you anything.

BILL: It's okay, it was cheap.

CHOIR OC: ♫ Oh, what fun it is to ridein a one-horse open sleigh. ♫

Later, wearing Christmas Cracker paper hats, and with plates of nibbles on the desk.

BILL: Going anywhere for Christmas?

DOCTOR; I never go anywhere.

BILL: That's not true. You go places, I can tell. My mum always said, 'With some people you can smell the wind in their clothes.'

DOCTOR: Oh. She sounds nice.

BILL: She died when I was a baby.

DOCTOR: Oh.

BILL: Yeah.

DOCTOR: If she died when you were a baby, when did she say
that?

BILL: In my head. I'm supposed to look like her, but I don't really know. There's hardly any photographs. She hated having her picture taken. But if someone's gone, do pictures really help?

He glances at the photographs on his desk.

BILL'S HOME

MOIRA: I thought you'd enjoy choosing something for yourself, as you're always passing judgements.

Bill's present is two £10 notes, Moira's is a scarf.

MOIRA: I hope you didn't spend too much on this.

BILL: Nah. This should cover it. What's that?

MOIRA: Oh, I found that at the back of the cupboard with all your old stuff. Just photographs of your mum. I didn't know we had 'em.

Bill opens the cardboard box. There are dozens if not hundreds of photographs, and she is moved to tears. Then she spots a reflection in a mirror of the Doctor taking the picture in one of the photographs.

OFFICE

As the clock chimes six.

BILL: Happy new term!

DOCTOR: With you in a moment.

Bill sees that the TARDIS is partly sitting on her gift rug.

BILL: You said you needed a crane to lift your box.

DOCTOR OC: Sorry, what did you say?

SERVICE AREA

Warmer weather, Bill is in short sleeves. She returns to the site of the puddle and sees Heather standing there.

BILL: Hey! Still making eyes at a puddle?

HEATHER: Did you ever work out what was wrong with your reflection?

BILL: Nah.

HEATHER: Come round. I'll show you.

BILL: Promise you won't go?

HEATHER: Promise.

But when Bill gets around the fencing, Heather is gone.

BILL: Okay. Yeah, no worries.

She leaves, not having seen Heather's screaming face in the puddle.

ALIEN VOICE OC: Pilot confirmed. Pilot engaged.

OFFICE

Bill enters as the Doctor is writing.

DOCTOR: What's wrong?

A little later.

BILL: She said it was a defect, but what kind of defect puts a star in your eye? But that doesn't even matter because she was right. There was something wrong when you looked in the puddle. That was definitely my face. I see my face all the time. I've never liked it, it's all over the place. It's always doing expressions when I'm trying to be enigmatic. I know my face, and there was something wrong with my face in the puddle. What could be wrong with your own face?

She looks out of the window to see the Doctor running along the path outside.

QUADRANGLE

BILL: Doctor!

She gives chase.

BILL: Doctor!

SERVICE AREA

The Doctor is looking into the puddle. We get to look up at him, with bubbles rising.

BILL: Why do you run like that?

DOCTOR: Like what?

BILL: Like a penguin with its arse on fire.

DOCTOR: Ergonomics. That's my face, yeah?

BILL: You seem a bit flexible on the subject.

DOCTOR: Oh, you've no idea.

BILL: Maybe it's got to do with that thing in her eye.

DOCTOR: How?

BILL: Maybe she's like, affected by something.

DOCTOR: By what?

BILL: I don't know. Look, I know you know lots of stuff about, well, basically everything, but do you know any sci-fi?

The Doctor straightens up.

DOCTOR: Go on.

BILL: Well, what if she's possessed. Something like that.

DOCTOR: Possessed by what?

BILL: I don't know. I saw this thing on Netflix. Lizards in people's brains.

DOCTOR: Right. So, you meet a girl with a discoloured iris and your first thought is she might have a lizard in her brain? I can see I'm going to have to up my game. Oh.

BILL: What?

DOCTOR: Oh!

BILL: What is it, what?

DOCTOR: Oh, I get it. I see it. It was easy for your friend because of her eye.

BILL: What, because it gives her special powers?

DOCTOR: No! Because her face isn't symmetrical. Look! Look into the puddle. Your face looks wrong, because it looks right. What's the one thing you never see when you look at a reflection? Your face. You never see your face the right way round. Right. Look for a freckle or a funny tooth. Something that's not symmetrical.

BILL: My badge!

DOCTOR: See, your friend saw it straightaway because of her eye.

BILL: But, it's moving like a reflection.

DOCTOR: It's not reflecting you. It's mimicking you. There's something in the water pretending to be you.

He scoops some up into a test tube, and puts a cork in it.

DOCTOR: Of course. It isn't water. Now what are these? Let's have a look.

BILL: What are they?

DOCTOR: Scorch marks. Interesting.

Wideshot: six scorch marks in a hexagonal pattern.

DOCTOR: Right, you. Let's get you on the bus.

BILL: The what? The bus?

DOCTOR: Tutorial's over, take the night off. It's all cancelled. Go and be a proper student. Texts, snogging, a vegan wrap.

BILL: But what about the puddle?

DOCTOR: Oh, it's just some freak optical effect. I'm bored already.

ALIEN VOICE OC: Passenger selected. Pursuit engaged.

Heather's hand reaching out. The puddle moves slowly.

BILL'S HOME

Water is running in the bathroom. She knocks on the door.

BILL: Hey. I'll make you a cuppa for the bath.

She goes to the kitchen and her mobile phone rings.

BILL: Hey.

MOIRA OC: Sorry I'm not there, love, but I think we both know it's time I treated myself.

Moira is at the bar.

BILL: Are you with Neville?

MOIRA OC: Why would I be back with Neville after last time?

BAR

MOIRA: Why do you think I'm such an idiot?

BILL'S HOME

Checking the caller ID.

BILL: Well, you're calling from his phone. Is there someone staying here in the flat?

MOIRA OC: Of course not, no. What are you talking about?

BILL: Er, nothing. Never mind. I'll see you tomorrow.

The water stops running, and now sounds like someone taking a bath.

BILL: Hello? Is someone in there? Is that Barry? Because she's with Neville, and it's not my fault.

Squelch of wet feet. Bill grabs an umbrella.

BILL: Sorry, I need to know who's in there. I'm coming in. Do you hear me? Make yourself decent.

She goes into the bathroom. The bath is empty, the last drops gurgling down the plughole. There is a shadowy shape behind the shower curtain.

BILL: If that's Barry, let's not make this worse. Just say it's you.

She pulls the curtain aside, as the last of the water drains away. Then Heather's eye looks up at her from the drain hole. She gasps and falls backwards, then runs out of the flat.

SHOPPING CENTRE

Bill running, bumping into people walking the other way.

MAN: Hey!

QUADRANGLE

Bill sees the Doctor is up in his office. Heather is standing nearby, with the sound of trickling water.

BILL: Hello.

HEATHER: Hello.

BILL: You scared me.

HEATHER: You scared me.

Bill slowly steps forward and can see the water dribbling from Heather's mouth and running off her hands. In fact, it is pouring off her entire body.

BILL: You're dead.

HEATHER: You're dead.

Heather leaps forward.

OFFICE

Bill bursts in as the Doctor is analysing the liquid from the puddle. She jams a chair under the door handle. There is a loud sound of water.

DOCTOR: Hello, Bill.

BILL: Oh!

The liquid starts to seep in under the door.

DOCTOR: What's that?

Heather starts to form from the liquid.

BILL: I'll tell you what it isn't. It isn't a freak optical effect.

BILL: And it's following me. Oh.

The Doctor starts to reach for Heather.

BILL: No, no, what are you doing?

DOCTOR: I'll tell you what, let's just pop into my box.

BILL: Your box? What good is getting in your box going to do?

DOCTOR: What an extraordinarily long and involved answer this is going to be.

TARDIS

The Doctor shuts the door, then opens it again to grab the Out of Order sign, and shuts it.

BILL: How do we stop it getting in? We're trapped in here!

DOCTOR: Nothing gets through these doors.

BILL: But they're made of wood. They've got windows!

The Doctor goes down the ramp and turns on the power. Bill doesn't turn around.

BILL: Look, this is all mad, I know, but that's the girl I told you about. Heather. Only I don't think it's really her. I know this is hard to believe. I know you're not exactly a sci-fi person-

Then she turns around.Theme music starts playing

DOCTOR: Time And Relative Dimension In Space. TARDIS for short. You're safe in here. You're safe in here and you always will be. Any questions?

BILL: Is this a knock-through?

DOCTOR: Well, in a way, yes.

BILL: Look at this place. It's like a-

DOCTOR: Spaceship.

BILL: Kitchen.

DOCTOR: A what?

BILL: A really posh kitchen, all metal. What happened with the
doors, though? Did you run out of money?

upbeat melody
DOCTOR: What you are standing in is a technological marvel. It is science beyond magic. This is the gateway to everything that ever was, or ever can be.

BILL: Can I use the toilet?

DOCTOR: Pardon?

BILL: I've had a fright. I need the toilet.

DOCTOR: It's down there, first right, second left, past the macaroon dispenser.

BILL: Thanks.

Nardole is coming up the stairs as Bill heads down.

NARDOLE: Oh, human! Human alert. Do you want me to repel her?

DOCTOR: She's just passing through. She just wants to use the toilet.

NARDOLE: Oh. I'd er, give it a minute, if I were you.

Boom! The TARDIS judders.

NARDOLE: Ooo, what was that?

DOCTOR: We have an incursion on campus. Extra-terrestrial. We're under attack.

Wet Heather is on the scanner.

DOCTOR: Let's move.

The TARDIS dematerialises.

BILL: Oh, my God! This isn't just a room, is it?

DOCTOR: No, it's not just a room.

BILL: This is a lift!

The TARDIS materialises.

NARDOLE: Well, come on, then.

CELLAR

DOCTOR: No interference here, as far as I can see. The vault's secure.

BILL: So your box can move? It can go anywhere it likes?

NARDOLE: Mmm. Good, innit?

BILL: Anywhere at all, in the whole university?

The Doctor scans the vault door with his screwdriver.

DOCTOR: Is it my imagination, or is this taking longer than normal?

Bill looks back inside the TARDIS.

BILL: Hang on. The room's still inside the box. This isn't a knock-through.

DOCTOR: No.

BILL: Doctor! It's bigger on the inside than it is on the outside!

NARDOLE: Way-hey! We got there!

Nardole and the Doctor shake hands.

BILL: How is that possible? How do you do that?

NARDOLE: Well, first you have to imagine a very big box fitting inside a very small box.

BILL: Okay.

NARDOLE: Then you have to make one. It's the second part people normally get stuck on.

DOCTOR: Can we shut up, please? Busy, busy. I need to know if there's any interest in what's inside this vault.

BILL: Why, what's inside it?

DOCTOR: Something I don't want anyone being too curious about.

BILL: So you put it in the middle of a university?

NARDOLE: Ooh, valid point. Yeah, nice.

DOCTOR: Either the creature came here specifically for what's in here, or it's just a coincidence.

BILL: It's just a coincidence.

DOCTOR: Well, we can't know that for sure.

BILL: Yeah, we can. It was here for ages before it did anything. If it had work to do, why would it lie around in a puddle?

DOCTOR: I don't know. Maybe it's a student?

NARDOLE: Oh, laughs banter. It's good, this. Your go again.

Liquid is pouring down the cellar steps.

DOCTOR: Nardole, we need to move away from the doors and towards the TARDIS.

Liquid pours down the steps, then Heather rises from the puddle at the bottom.

NARDOLE: What if it attacks us?

DOCTOR: Well, that's the good news. It means it's not interested in what's inside the vault. It just wants to kill us.

NARDOLE: Oh.

DOCTOR: Run!

Heather screams.

TARDIS

DOCTOR: It's not interested in the vault, it's chasing us. Let's give it a proper challenge. Let's see how far she's prepared to go.

The TARDIS dematerialises.

BILL: But what about my friend? What about Heather? Can you save her?

And materialises.

DOCTOR: First things first. Let's see if we can survive her.

The Doctor goes outside. Nardole shrugs.

SYDNEY HARBOUR

Bright sunshine, seagulls, water and a modern cityscape on the other side. Passers-by completely ignoring the blue box.

BILL: But

DOCTOR: Yes.

BILL: We've moved again.

DOCTOR: We have.

BILL: It was night.

DOCTOR: Yep.

BILL: Now it's day. Definitely day.

BILL: Oh, my God! Have we travelled in time?

DOCTOR: No, of course not. We've travelled to Australia.

He steps aside to reveal Sydney Opera House on the other side of the harbour. I guess we are supposed to be in Kirribilli, from the angle.

RESTROOM

Bill dashes in to splash her face with water.

DOCTOR: How are you doing?

BILL: How do you think?

DOCTOR: Right. Um, how do I help?

BILL: Can I ask you a personal question?

DOCTOR: No.

BILL: Can I anyway?

DOCTOR: Yes.

BILL: Are you from space?

DOCTOR: No, of course not. Nobody's from space. I'm from a
planet like everybody else.

BILL: This planet?

DOCTOR: No, not specifically this one.

BILL: Doesn't make sense, then.

DOCTOR: What doesn't?

BILL: TARDIS. If you're from another planet, why would you name your box in English? Those initials wouldn't work in any other language!

DOCTOR: People don't generally bring that up.

BILL: It looks like a phone box.

DOCTOR: Yes. Er, well, that's the cloaking device. It sort of hides itself.

BILL: It's hidden itself as a box with 'pull to enter' on the front?

DOCTOR: Uh-huh. It's stuck. It's supposed to blend in, but it's, it's broken.

Bill laughs, then the sink gurgles. Water appears on the mirror.

BILL: Doctor...

Café

DOCTOR: Out, out! Everybody out! Shark attack!

Heather comes out of the restroom, screaming. Everybody flees.

TARDIS

In flight

BILL: Where are we going?

DOCTOR: As far as we can. She made Australia in a minute. Let's see what she can really do.

NARDOLE: Sir, we're leaving Earth. What about the vault?

DOCTOR: Oh, we're fine. If there's any trouble, I'll get a message on this. The psychic paper.

DOCTOR: Let's see how long it takes her to get here.

The TARDIS materialises.

BILL: Where are we?

DOCTOR: Other end of the universe. Twenty three million years in the future. Oh, yes, it's a time machine too.

Planet surface

Filmed in a quarry with extra lovely rock formations on top, all wind carved arches and glittering fluorspar crystals.

BILL: So this is somewhere else? This is a different planet? Not Earth, a different one?

DOCTOR: That's the general idea.

BILL: That's different sky? Is it made of something different? What is sky made of?

DOCTOR: Lemon drops.

BILL: Really?

DOCTOR: No, but wouldn't that be nice?

NARDOLE: You can be very silly sometimes, you know that? So how do we know this water thing is actually dangerous?

DOCTOR: Ah, because most things are.

NARDOLE: Mmm, that's true.

BILL: Why? Is everything out here evil?

DOCTOR: Hardly anything is evil, but most things are hungry. Hunger looks very like evil from the wrong end of the cutlery. Or do you think that your bacon sandwich loves you back?

NARDOLE: So what is it, and what was it doing on Earth?

DOCTOR: Well, there were scorch marks on the concrete where we found it. Could have been left by a shuttlecraft. The puddle, what did it look like? I mean, if that was a car, what would you say that was?

BILL: An oil leak? So it's space engine oil?

DOCTOR: Intelligent oil. Super intelligent space oil. No, part of the ship itself. Shape-shifting fluid that becomes anything it needs to be.

BILL: Seriously?

DOCTOR: But it spent ages laying around being a puddle. What changed? Your friend. She looked into it, didn't she? More than once.

BILL: So?

DOCTOR: Maybe it saw something it needed. What was she like, your friend? What did she want? What did she need?

HEATHER memory: Everywhere I go, I just want to leave.

BILL: I think she wanted to leave.

DOCTOR: You see?

NARDOLE: The puddle found a passenger.

DOCTOR: A left-behind droplet of a liquid spaceship. A single tear drop, alone in a strange world. Then, one day, it finds someone who wants to fly away.

Bill finds a puddle of liquid amongst the rocks.

DOCTOR: Not just a passenger. More than a passenger, it found a pilot, so it ate her.

NARDOLE: So why is it chasing this one?

DOCTOR: Everything wants, everything needs.

NARDOLE: But why does it want her?

DOCTOR: I don't know. I don't know everything, Nardole. I don't have it all written down.

NARDOLE: You act like you do.

DOCTOR: I act like I do, because I don't.

NARDOLE: It must be looking for something.

Bill bends down over the puddle, and Heather rises up slowly to the surface.

DOCTOR: Of course it is, everything is.

NARDOLE: But what?

DOCTOR: What, in the end, are any of us looking for? We're looking for someone who's looking for us.

BILL memory: Hey, still making eyes at a puddle?

Then Heather screams, grabs Bill's face, and tries to pull her down.

DOCTOR: Bill! Bill! Quick!

The Doctor and Nardole pull Bill free.

DOCTOR: Back to the TARDIS!

A geyser erupts from the puddle and forms a face.

TARDIS

DOCTOR: Okay, it's fast. It time travels. It never gives up.

The TARDIS zooms through space.

DOCTOR: Plan! Basic sterilisation. We're going to run that thing through the deadliest fire in the universe.

NARDOLE: Yes, that sounds excellent. The deadliest fire in the universe. That's definitely good.

BILL: How do we do that?

DOCTOR: The only way we can. We run through it first.

NARDOLE: Less good now.

The TARDIS shakes. Nardole looks at the scanner.

NARDOLE: No, not there. I don't like it there!

The Doctor grabs a sonic screwdriver.

DOCTOR: Nardole!

NARDOLE: I don't like there.

The Doctor throws the sonic screwdriver to Nardole, who catches it.

DOCTOR: I want you running interference. Can you do that?

NARDOLE: Can I say no, sir?

DOCTOR: No.

NARDOLE: Yes, then.

DOCTOR: Thank you.

NARDOLE: But no really.

BILL: Where are we?

DOCTOR: Well, we're basically in the middle of a war. No, but, well, it's a war zone, and this is just your basic skirmish. And it's not as bad as it sounds, I promise you. Come on, I've got friends here, old friends.

NARDOLE: Oh...

SPACECRAFT

A metal ribbed corridor.

DOCTOR: I say friends.

DALEK OC: The Doctor is detected. Seek. Locate. Destroy.

Nardole is close to tears. The Doctor and Bill run through explosions.

BILL: Are we still in the future?

DOCTOR: No. This is the past.

BILL: Doesn't, doesn't look like the past. Are we safe here?

DOCTOR: Well, that's up to Nardole, so probably not.

Nardole's job is to sonic control boxes, making them go bang. He keeps whimpering as he runs.

NARDOLE: Oh! Oh, another. Oh! Oh, another. Keep moving, Doctor!

BILL: Where are we going?

DOCTOR: Into the fire. Come on.

Shouts and screams getting louder.

MOVELLAN: Move! Move! Move!

BILL: Who are those guys?

DOCTOR: Never mind them, it's who they're firing at.

Big explosions, Movellans thrown against the bulkheads. And behind them, wet Heather.

DOCTOR: Come on.

The Doctor and Bill run around a corner and stop at the sight of a giant pepper pot on wheels armed with a gun and a very aggressive looking sink plunger.

BILL: What's that?

DOCTOR: The deadliest fire in the universe.

DALEK: Identify. Intruder. Identify.

DOCTOR: holding out screwdriver Scan this device and identify me!

DALEK: You are the Doctor. You are an enemy of the Daleks!

DOCTOR: Oh, yes, I am!

DALEK: Exterminate!

The Doctor drags Bill out of the way as the Dalek fires. Its weapons fire goes straight through Heather.

HEATHER: Exterminate.

DALEK: Exterminate!

HEATHER: Exterminate.

Meanwhile, Nardole is trying to blow up another panel.

NARDOLE: Come on.

DALEK 2: Exterminate!

NARDOLE: Ah!

Nardole runs, dodging Dalek fire.

BILL: What was that thing?

DOCTOR: A Dalek.

BILL: A what?

DOCTOR: A Dalek.

BILL: What's a Dalek?

DOCTOR: Never mind. It's a Dalek.

They run.

DALEK OC: Exterminate!

They stop as a blast whizzes straight between them and sets the corridor ahead on fire, then turn.

DALEK: slowing down Exterminate.

DOCTOR: That's wrong. I know my Daleks, and that's wrong. Oh, I see.

BILL: You see what?

The Doctor is staring into the Dalek's eye stalk.

NARDOLE: I've sealed the area. All the Daleks are quarantined. Except that one.

DOCTOR: It's okay. This isn't a Dalek. Look. Look at the eye.

A human eye with a five-pointed star pattern on the iris.

BILL: Heather.

Water starts to pour off the Dalek, then it dissolves, and Heather stands up.

HEATHER: Heather.

The Doctor walks around Heather, so she has to turn away from Bill.

DOCTOR: Interesting. You had a gun but you didn't use it. Why? You've already taken one person from the Earth. I'm going to let that pass, because I have to, but I will not let you take another. Go. Just go now. Fly away. Why won't you just go?

Heather turns back to Bill, and Bill remembers why.

memory:
BILL Promise you won't go?

memory:
HEATHER Promise.

BILL: Oh, my God. I understand.

NARDOLE: You what?

BILL: The last thing she said to me. She promised she wouldn't leave without me.

DOCTOR: Her last conscious thought, driving her across the universe. Never underestimate a crush.

NARDOLE: Oh, you don't have to tell me.

BILL: What do we do?

DOCTOR: I don't know. She's not chasing you, she's inviting you. Release her. Release her from her promise.

BILL: You have to let me go.

HEATHER: You have to let me go.

BILL: I will.

HEATHER: I will.

BILL: I really liked you.

HEATHER: I really liked you.

Heather reaches out to Bill, and Bill raises her hand too.

DOCTOR: Bill, don't. Don't!

NARDOLE: Don't do that. Listen, please, just listen to him.

DOCTOR: Don't. Don't! Bill, let go!

Bill and Heather clasp hands, and Bill is shown endless worlds, their meeting in bar.

DOCTOR OC: Bill, listen to me. Whatever she's showing you, whatever she's letting you see. It's a lure, it's a trap. She's making you part of her, and you can never come back.

BILL OC: I see what you see. It's beautiful.

DOCTOR: Bill, let go! You have to let go! She is not human any more.

BILL: Goodbye, Heather.

HEATHER: Goodbye, Bill.

Bill lets go. The Doctor pulls her away from Heather.

DOCTOR: Bill!

Heather dissolves into a puddle.

DOCTOR: You all right?

BILL: Yeah, I think so.

NARDOLE: You don't look all right.

DOCTOR: She's fine.

NARDOLE: That's the Doctor for you. Never notices the tears.

BILL: I don't think they're mine.

OFFICE

Bill is sitting by the desk as the Doctor comes out of the TARDIS.

DOCTOR: The vault alarm went off, but it was nothing. A student was sick outside and it registered as a biological attack. laughs

BILL: I saw it all for a moment. Everything out there. She was going to let me fly with her. She was inviting me. I was too scared.

DOCTOR: Scared is good. Scared is rational. She wasn't human any more.

BILL: Will we see her again?

DOCTOR: I don't see how.

Bill looks across at the TARDIS.

DOCTOR: No, no, no, no. No, no. You have to forget about that.

BILL: I don't see how I can.

DOCTOR: I do. Come here, Bill.

She stands in front of him.

BILL: What's up?

DOCTOR: I just want to fix something.

He reaches for her head.

BILL: Whoa! What are you doing?

DOCTOR: Don't worry. This won't hurt at all.

BILL: No, but tell me.

DOCTOR: Nothing.

BILL: Yeah, because I think you're going to wipe my memory. I'm not stupid, you know. That's the trouble with you. You don't think anyone's ever seen a movie. I know what a mind-wipe looks like!

DOCTOR: I have no choice. I'm here for a reason. I am in disguise. I have promises to keep. No one can know about me.

BILL: This is the most exciting thing that's ever happened to me in my life. The only exciting thing!

DOCTOR: I'm sorry.

BILL: Okay, let me remember just for a week. Just a week. Okay, well, just for tonight. Just one night. Come on, let me have some good dreams for once. Okay. Do what you've got to do. But imagine, just imagine how it would feel if someone did this to you.

Big pause as Bill braces herself with her eyes closed, then he taps her on the chin.

DOCTOR: Get out.

BILL: What?

DOCTOR: You can keep your memories. Now get out before I change my mind! Don't speak, don't start, just run! Now. Go!

Bill runs out of the room. The Doctor sees the picture of Susan.

DOCTOR: Shut up. You shut up as well.

Susan, Melody. A small time rotor noise from the TARDIS.

DOCTOR: Will you all please just leave me alone? I can't do that any more. I promised!

Outside, Bill checks that she can still remember Heather, and smiles.

QUADRANGLE

DOCTOR: It's a big universe, but maybe one day we'll find her.

The Doctor is standing next to the TARDIS.

BILL: What changed your mind?

DOCTOR: Time.

BILL: Time?

DOCTOR: And Relative Dimension In Space.

He clicks his fingers and the TARDIS door opens.

DOCTOR: It means, what the hell?

Bill joins him in the TARDIS.

NEXT TIME: