[Tardis]

(The Tardis lands, and the Doctor puts on the hand brake.)

DOCTOR: There we go. Perfect landing. Which isn't easy in such a tight spot.

MARTHA: You should be used to tight spots by now. Where are we?

DOCTOR: The end of the line. No place like it.

(Martha goes outside.)

[Martha's home]

(The Tardis is next to the clothes horse.)

MARTHA: Home. You took me home?

DOCTOR: In fact, the morning after we left, so you've only been gone about twelve hours. No time at all, really.

MARTHA: But all the stuff we've done. Shakespeare, New New York, old New York?

DOCTOR: Yep, all in one night, relatively speaking. Everything should be just as it was. Books, CDs, laundry. So, back were you were, as promised.

MARTHA: This is it?

DOCTOR: Yeah, I should probably er

(Martha's phone rings and the answering machine starts up.)

MARTHA [on machine]: Hi, I'm out. Leave a message.

MARTHA: I'm sorry.

FRANCINE [on machine]: Martha, are you there? Pick it up, will you?

MARTHA: It's Mum. It'll wait.

FRANCINE: All right then, pretend that you're out if you like. I was only calling to say that your sister's on TV. On the news of all things. Just thought you might be interested.

(Martha turns on the television, which was on stand by.)

LAZARUS [on television]: The details are top secret

MARTHA: How could Tish end up on the news?

(Tish is standing next to an elderly man who is making an announcement.)

LAZARUS [on television]: Tonight, I will demonstrate a device which will redefine our world.

MARTHA: She's got a new job. PR for some research lab.

LAZARUS [on television]: With the push of a single button, I will change what it means to be human.

REPORTER [on television]: Professor! Professor!

(Martha puts the TV back on standby.)

MARTHA: Sorry. You were saying we should?

DOCTOR: Yes, yes, we should. One trip is what we said.

MARTHA: Yeah. I suppose things just kind of escalated.

DOCTOR: Mmm. Seems to happen to me a lot.

MARTHA: Thank you. For everything.

DOCTOR: It was my pleasure.

(The Doctor goes back into the Tardis, and it dematerialises. Then it materialises again.)

DOCTOR: No, I'm sorry. Did he say he was going to change what it means to be human?

[Lazarus's office]

(On the desk is a replica of Michaelangelo's David, and a model of a cathedral is on a stand. An older woman is speaking to the elderly man.)

LADY THAW: Are you sure it's safe?

LAZARUS: There were some issues. They've been resolved. I'm confident I'm in no serious danger.

LADY THAW: That's comforting, Richard, but it wasn't just you I was worried about.

LAZARUS: Your concern is touching.

LADY THAW: The people in that room will represent billions of pounds worth of potential investment. Mister Saxon wants to be sure they like what they see.

LAZARUS: Don't worry. Our friend will get his money's worth.

(Tish enters.)

TISH: You wanted to see the guest list for tonight, Professor?

LAZARUS: Yes. Thank you, Leticia.

(She puts the file on his desk, and he puts his hand on hers.)

LAZARUS: That's an interesting perfume. What's it called?

TISH: Soap.

(Tish pulls her hand away and leaves.)

[Street]

(The Doctor and Martha are in formal evening dress.)

DOCTOR: Oh, black tie. Whenever I wear this, something bad always happens.

MARTHA: It's not the outfit, that's just you. Anyway, I think it suits you. In a James Bond kind of way.

DOCTOR: James Bond? Really?

(They walk up to a building labelled Lazarus Laboratories.)

[Reception room]

(In the middle of the room is a circular dais. On it is a man-sized frosted glass chamber and four upright posts, slightly curved at the top to aim at the chamber. A waiter walks past with a tray of food.)

DOCTOR: Oh, look, they've got nibbles! I love nibbles.

TISH: Hello.

MARTHA: Tish.

TISH: You look great. So, what do you think? Impressive, isn't it?

MARTHA: Very.

TISH: And two nights out in a row for you. That's dangerously close to a social life.

MARTHA: If I keep this up, I'll end up in all the gossip columns.

TISH: You might, actually. You should keep an eye out for photographers. And Mum, she's coming too. Even dragging Leo along with her.

MARTHA: Leo in black tie? That I must see. This is, er, the Doctor.

DOCTOR: Hello.

TISH: Is he with you?

MARTHA: Yeah.

TISH: But he's not on the list. How did he get in?

MARTHA: He's my plus one.

DOCTOR: So, this Lazarus, he's your boss?

TISH: Professor Lazarus, yes. I'm part of his executive staff.

MARTHA: She's in the PR department.

TISH: I'm head of the PR department, actually.

MARTHA: You're joking.

TISH: I put this whole thing together.

DOCTOR: So do you know what the professor's going to be doing tonight? That looks like it might be a sonic microfield manipulator.

TISH: He's a science geek. I should have known. Got to get back to work now. I'll catch up with you later.

DOCTOR: Science geek? What does that mean?

MARTHA: That your obsessively enthusiastic about it.

DOCTOR: Oh, nice.

(Francine enters with Leo.)

FRANCINE: Your father's caused me enough heartache already with his menopause and his trophy girlfriend.

LEO: Yeah, Mum, I know. It's just something he said last night.

FRANCINE: Martha.

MARTHA: Mum!

(Martha gives her mother a big hug.)

FRANCINE: All right, what's the occasion?

MARTHA: What do you mean? I'm just pleased to see you, that's all.

FRANCINE: You saw me last night.

MARTHA: I know. I just miss you. You're looking good, Leo.

LEO: Yeah. If anyone asks me to fetch them a drink, I'll swing for him.

FRANCINE: You disappeared last night.

MARTHA: I just went home.

FRANCINE: On your own?

MARTHA: This is a friend of mine. The Doctor.

FRANCINE: Doctor what?

MARTHA: No, it's just the Doctor. We've been doing some work together.

LEO: You all right, mate?

DOCTOR: It's lovely to meet you, Mrs Jones. Heard a lot about you.

FRANCINE: Have you? What have you heard, then?

DOCTOR: Oh, you know, that you're Martha's mother and. Er, no, actually, that's about it. We haven't had much time to chat. You know, been busy.

FRANCINE: Busy? Doing what, exactly?

DOCTOR: Oh you know. Stuff.

(Professor Lazarus taps on his glass for attention.)

LAZARUS: Ladies and gentlemen, I am Professor Richard Lazarus and tonight I am going to perform a miracle. It is, I believe, the most important advance since Rutherford split the atom, the biggest leap since Armstrong stood on the moon. Tonight, you will watch and wonder. Tomorrow, you will wake to a world which will be changed forever.

(Lazarus goes inside the chamber. A pair of lady scientists start up the machine and press a big red button. The four columns start to oscillate and rotate around the chamber as they pour energy into it. Then an alarm sounds.)

DOCTOR: Something's wrong. It's overloading.

(The computer agrees. There are sparks from the controls, then smoke. The Doctor rushes over and gets out his sonic screwdriver.)

LADY THAW: Somebody stop him. Get him away from those controls!

DOCTOR: If this thing goes up, it'll take the whole building with it. Is that what you want?

(Finally, the Doctor pulls out a big power cable and the contraption slows down, then stops. Martha rushes to the chamber.)

DOCTOR: Get it open!

(Martha opens the door, and a young man staggers out. Lady Thaw is delighted.)

LAZARUS: Ladies and gentlemen, I am Richard Lazarus. I am seventy six years old and I am reborn!

(Wild applause.)

LADY THAW: He did it. He actually did it.

(A little later, Lazarus is posing for the photographers.)

MARTHA: It can't be the same guy. It's impossible. It must be a trick.

DOCTOR: Oh, it's not a trick. I wish it were.

MARTHA: What just happened then?

DOCTOR: He just changed what it means to be human.

LADY THAW: Excuse me. That was the most astonishing thing I've ever seen. Look at you.

LAZARUS: This is only the beginning. We're not just making history, we're shaping the future, too.

LADY THAW: Think of the money we'll make. People will sell their souls to be transformed like that. And I'll be first in line.

(Lazarus stiffens and gasps, then grabs a tray from a passing waiter and proceeds to eat all the food on it.)

LADY THAW: Richard.

LAZARUS: I'm famished.

DOCTOR: Energy deficit. Always happens with this kind of process.

LAZARUS: You speak as if you see this every day, Mister?

DOCTOR: Doctor. And well, no, not every day, but I have some experience of this kind of transformation.

LAZARUS: That's not possible.

DOCTOR: Using hypersonic sound waves to create a state of resonance. That's inspired.

LAZARUS: You understand the theory, then.

DOCTOR: Enough to know that you couldn't possibly have allowed for all the variables.

LAZARUS: No experiment is entirely without risk.

DOCTOR: That thing nearly exploded. You might as well have stepped into a blender.

LADY THAW: You're not qualified to comment.

DOCTOR: If I hadn't stopped it, it would have exploded.

LAZARUS: Then I thank you, Doctor. But that's a simple engineering issue. What happened inside the capsule was exactly what was supposed to happen. No more, no less.

MARTHA: You've no way of knowing that until you've run proper tests.

LAZARUS: Look at me. You can see what happened. I'm all the proof you need.

LADY THAW: This device will be properly certified before we start to operate commercially.

MARTHA: Commercially? You are joking. That'll cause chaos.

LAZARUS: Not chaos, change. A chance for humanity to evolve, to improve.

DOCTOR: This isn't about improving. This is about you and your customers living a little longer.

LAZARUS: Not a little longer, Doctor. A lot longer. Perhaps indefinitely.

LADY THAW: Richard, we have things to discuss, upstairs.

LAZARUS: Goodbye, Doctor. In a few years, you'll look back and laugh at how wrong you were.

(Lazarus kisses Martha's hand, and leaves with Lady Thaw.)

DOCTOR: Oh, he's out of his depth. No idea of the damage he might have done.

MARTHA: So what do we do now?

DOCTOR: Now? Well, this building must be full of laboratories. I say we do our own tests.

MARTHA: Lucky I've just collected a DNA sample then, isn't it?

DOCTOR: Oh, Martha Jones, you're a star.

[Lazarus' office]

LAZARUS: I grew up over there. A tiny flat above a butcher's shop.

LADY THAW: It'll have a blue plaque soon. Richard Lazarus lived here.

LAZARUS: It's gone. Destroyed in the war. The bombing.

LADY THAW: Of course.

LAZARUS: 1940. Do you remember? Night after night. Explosions, guns, firestorm.

LADY THAW: My parents had sent me to the country by then.

LAZARUS: When the sirens went, we'd go to the cathedral there. We used to shelter in the crypt. The living cowering among the dead.

LADY THAW: But look at what you've built here, now. You've laid the foundations for an empire. An empire we can rule together. (She pulls him in for a kiss, and he pulls back in disgust.)

LADY THAW: Well, what's wrong?

LAZARUS: Look at yourself, woman.

[Laboratory]

(An image of a strand of DNA is on the computer screen.)

DOCTOR: Amazing.

MARTHA: What?

DOCTOR: Lazarus's DNA.

MARTHA: I can't see anything different.

DOCTOR: Look at it.

MARTHA: Oh, my God. Did that just change? But it can't have.

DOCTOR: But it did.

MARTHA: It's impossible.

DOCTOR: And that's two impossible things we've seen so far tonight. Don't you love it when that happens?

MARTHA: That means Lazarus has changed his own molecular patterns.

DOCTOR: Hypersonic sound waves to destabilise the cell structure, then a metagenic programme to manipulate the coding in the protein strands. Basically, he hacked into his own genes and instructed them to rejuvenate.

MARTHA: But they're still mutating now.

DOCTOR: Because he missed something. Something in his DNA has been activated and won't let him stabilise. Something that's trying to change him.

MARTHA: Change him into what?

DOCTOR: I don't know, but I think we need to find out.

MARTHA: That woman said they were going upstairs.

DOCTOR: Let's go.

[Lazarus' office]

LADY THAW: It's me who made this all possible. This is my triumph, and I will not be denied, not by you, not after everything I've done.

LAZARUS: You backed me because you saw a profit. Your concern was financial.

LADY THAW: Well, you want the money as much as I do. We had a plan.

(Lazarus looks ill.)

LADY THAW: When the device is ready, I'll be rejuvenated, too. We could be rich and young and together.

LAZARUS: You think I'd waste another lifetime on you?

LADY THAW: Did that process make you even more cruel?

LAZARUS: No, my love. That I learnt from you. You have a gift for it.

LADY THAW: Then you know that I'll protect my involvement in the project. I'm sure Mister Saxon will be interested

(Lazarus gasps and pulls at his collar.)

LADY THAW: What's going on?

LAZARUS: It must just be, ah!

LADY THAW: What is it?

LAZARUS: I'll be fine in a moment. It's probably just cramp.

(His back suddenly arches with a nasty cracking sound. He falls to the floor, tugging at his bow tie and writhing.)

LADY THAW: Oh! Richard! Is it some sort of seizure? What should I do? I don't understand what's happening. Richard.

(Something very inhuman rears over the terrified woman, opens what one can only call a mouth, and lunges at her.)

[Reception room]

(A string quartet is playing.)

FRANCINE: Tish! Have you seen Martha and that Doctor anywhere?

TISH: Not since the demonstration.

FRANCINE: Do you know anything about him? Has she ever mentioned him before?

TISH: Not to me.

FRANCINE: The way she followed him.

TISH: She's a doctor. She was just doing her job.

FRANCINE: She's not a doctor yet. Never will be, if she doesn't stay focused.

LEO: Look, she's found a bloke. So what?

FRANCINE: There's something going on, Leo, I can feel it.

(The lift doors open and human Lazarus steps out. He has changed his shirt, and he stretches his neck in a very inhuman way.)

LAZARUS: Leticia Jones. I'd recognize the smell of that soap anywhere.

TISH: Professor.

LAZARUS: I'm sorry, ladies and gentlemen, you'll have to excuse me while I take care of Leticia here. I've been neglecting her.

[Lazarus' office]

MARTHA: This is his office, all right.

DOCTOR: So where is he?

MARTHA: Don't know. Let's try back at the reception.

(Martha sees a skeletal leg with a ladies shoe on it sticking out behind the desk. )

MARTHA: Is that Lady Thaw?

DOCTOR: Used to be. Now it's just a shell. Had all the life energy drained out, like squeezing the juice out of an orange.

MARTHA: Lazarus?

DOCTOR: Could be.

MARTHA: So he's changed already?

DOCTOR: Not necessarily. You saw the DNA. It was fluctuating. The process must demand energy. This might not have been enough.

MARTHA: So he might do this again?

DOCTOR: Mmm.

[By the lifts]

(The Doctor and Martha get into one lift just before another arrives.)

LAZARUS: You seem very young to have such a responsible position. Have you much experience?

TISH: Not really. But the interview panel thought I had all the necessary attributes.

LAZARUS: How perceptive of them.

TISH: So where are you taking me?

LAZARUS: Up to the roof. It's a lovely evening. I thought I'd show you the view. It's extraordinary.

TISH: Like a lot of things around here, then.

[Reception room]

MARTHA: I can't see him.

DOCTOR: He can't be far. Keep looking.

LEO: Hey, you all right, Marth? I think Mum wants to talk to you.

MARTHA: Have you see Lazarus anywhere?

LEO: Yeah, well, he was getting cosy with Tish a couple of minutes ago.

MARTHA: With Tish?

FRANCINE: Ah, Doctor.

DOCTOR: Where did they go?

LEO: Upstairs, I think. Why?

FRANCINE: Doctor

(The Doctor runs past her, spilling her drink. Martha follows him.)

FRANCINE: I'm speaking to you!

MARTHA: Not now, Mum.

(Francine gets a napkin from a table to try her arm.)

MAN: I think you need one of these.

(Another glass of champagne. )

FRANCINE: Thank you. That's very kind of you.

MAN: Do you know that man?

FRANCINE: No. He's a friend of my daughter's.

MAN: Perhaps she should choose her friends more carefully.

[Lazarus' office]

MARTHA: Where are they?

DOCTOR: Fluctuating DNA will give off an energy signature. I might be able to pick it up.

(He scans with his sonic screwdriver.)

DOCTOR: Got him.

MARTHA: Where?

(He points upwards.)

MARTHA: But this is the top floor. The roof.

[Roof]

(Looking north west towards St Paul's Cathedral, with the tower of the Collegiate Church of St Saviour and St Mary Overie in the foreground.)

TISH: That clock tower's beautiful all lit up like that.

LAZARUS: It's Southwark Cathedral. One of the oldest churches in London. Been around even longer than I have.

TISH: Well, you're looking pretty good for your age.

LAZARUS: Thank you.

TISH: Can I?

LAZARUS: Of course.

(She strokes his cheek.)

TISH: Still can't take it in.

LAZARUS: I'm still adjusting myself. I've been working toward it for so many years, it's hard to believe the moment's finally arrived.

TISH: And is it like you expected?

LAZARUS: I find that nothing's ever exactly like you expect. There's always something to surprise you. Between the idea and the reality, between the motion and the act

DOCTOR: Falls the Shadow.

(The Hollow Men, by TS Eliot.)

LAZARUS: So the mysterious Doctor knows his Eliot. I'm impressed.

TISH: Martha, what are you doing here?

MARTHA: Tish, get away from him.

TISH: What? Don't tell me what to do.

DOCTOR: I wouldn't have thought you had time for poetry, Lazarus, what with you being busy defying the laws of nature and all.

LAZARUS: You're right, Doctor. One lifetime's been too short for me to do everything I'd like. How much more I'll get done in two or three or four.

DOCTOR: Doesn't work like that. Some people live more in twenty years than others do in eighty. It's not the time that matters, it's the person.

LAZARUS: But if it's the right person, what a gift that would be.

DOCTOR: Or what a curse. Look at what you've done to yourself.

LAZARUS: Who are you to judge me?

MARTHA: Over here, Tish.

TISH: You have to spoil everything, don't you? Every time I find someone nice, you have to go and find fault.

(Behind Tish's back, Lazarus spasms and falls.)

MARTHA: Tish, he's a monster!

TISH: I know the age thing's a bit freaky, but it works for Catherine Zeta-Jones.

(Then Tish turns and sees the transformation in progress. Lazarus is now a massive bony scorpion with a human face.)

TISH: What's that?

DOCTOR: Run!

[By the lifts]

(The Doctor sonics the roof door shut and they run down the stairs.)

MARTHA: Are you okay?

TISH: I was going to snog him.

(The lights flicker as the creature tries to break in.)

TANNOY: Security one. Security one. Security one.

(The lights go out and the doors all close.)

MARTHA: What's happening?

TISH: An intrusion. It triggers a security lockdown. Kills most of the power. Stops the lifts, seals the exits.

DOCTOR: He must be breaking through that door. The stairs, come on!

[Stairwell]

(Growl, crash.)

MARTHA: He's inside!

DOCTOR: We haven't got much time!

[Reception room]

DOCTOR: Tish, is there another way out of here?

TISH: There's an exit in the corner, but it'll be locked now.

DOCTOR: Martha, setting fifty four. Hurry.

(He throws the sonic screwdriver to Martha.)

DOCTOR: Listen to me! You people are in serious danger! You need to get out of here right now!

WOMAN: Don't be ridiculous. The biggest danger here is choking on an olive.

(Then the mutant Lazarus appears on the mezzanine, and jumps down, smashing a table. Panic.)

LEO: Mum, get back!

(The mutant's tail sends a table flying. It hits Leo. Meanwhile, Martha gets the exit door open.)

FRANCINE: Leo!

MARTHA: Over here! This way! Everyone downstairs now! Hurry!

(The mutant stands over the frozen woman and opens its jaws sideways. Then it brings its tail over, and the other mouth appears.)

DOCTOR: No! Get away from her!

(Too late. A desiccated corpse falls to the floor.)

(Francine goes to help her son.)

FRANCINE: Leo. Leo.

(The mutant turns to them.)

DOCTOR: Lazarus! Leave them alone.

(It turns towards the Doctor, and Martha runs to her family.)

FRANCINE: Martha.

MARTHA: Come on, stay with me. You're okay.

DOCTOR: What's the point? You can't control it. The mutation's too strong. Killing those people won't help you. You're a fool. A vain old man who thought he could defy nature. Only Nature got her own back, didn't she? You're a joke, Lazarus! A footnote in the history of failure!

(The Doctor leads the mutant off down a corridor.)

TISH: What's the Doctor doing?

MARTHA: He's trying to buy us some time. Let's not waste it. Leo, look at me. Focus on me. Let's see your eyes. He's got concussion. Mum, you'll need to help him downstairs.

(Martha puts some ice into a napkin.)

MARTHA: This'll keep the swelling down. Go! I'll be right behind you. Tish, move! We need to get out of here.

[Basement]

(The Doctor clambers amongst the pipes and control panels.)

LAZARUS: It's no good, Doctor. You can't stop me.

DOCTOR: Is that the same arrogance you had when you swore nothing had gone wrong with your device?

LAZARUS: The arrogance is yours. You can't stand in the way of progress.

DOCTOR: You call feeding on innocent people progress? You're delusional!

LAZARUS: It is a necessary sacrifice.

DOCTOR: That's not your decision to make.

[Main entrance]

(People are piling up against the glass doors.)

TISH: We can't get out. We're trapped!

MARTHA: There must be an override switch. Where's the security desk? Tish!

TISH: There.

(Martha jumps over the desk, goes to the control panel and runs the sonic screwdriver over it. The lights come on, the doors open, and the panicked crowd stream out.)

[Basement]

LAZARUS: Peek a boo.

(The mutant is hanging from the ceiling.)

DOCTOR: Oh, hello.

(The Doctor runs out and down another corridor.)

[Main entrance]

MARTHA: I've got to go back.

FRANCINE: You can't! You saw what that thing did. It'll kill you.

MARTHA: I don't care. I have to go.

FRANCINE: It's that Doctor, isn't it? That's what's happened to you. That's why you've changed.

TISH: He was buying us time, Martha. Time for you to get out, too.

MARTHA: I'm not leaving him.

FRANCINE: Martha!

[Laboratory]

(The Doctor jumps on a bench and starts to take a light fitting apart. Then he turns on a Bunsen burner and snuffs out the flame. He pulls another tube off a gas fitting and hides behind another bench.)

LAZARUS: More hide and seek, Doctor? How disappointing. Why don't you come out and face me?

(The Doctor turns on as much gas as he can.)

DOCTOR: Have you looked in the mirror lately? Why would I want to face that, hmm?

(The Doctor runs to the back door and hits the light switch as he leaves. KaBOOM goes the laboratory.)

[Corridor]

(The Doctor and Martha run into each other.)

DOCTOR: What are you doing here?

MARTHA: I'm returning this. I thought you might need it.

DOCTOR: How did you?

MARTHA: I heard the explosion. I guessed it was you.

DOCTOR: I blasted Lazarus.

MARTHA: Did you kill him?

(No.)

DOCTOR: More sort of annoyed him, I'd say.

[Outside the building]

TISH: She'll be all right. The Doctor and her, they'll look out for each other.

FRANCINE: She turned her back on us, went in there with that thing for him.

LEO: He must be some guy.

TISH: Maybe she loves him.

FRANCINE: She just met him.

MAN: Is you daughter still in there with the Doctor?

FRANCINE: Do you know him?

MAN: He's dangerous. There are things you should know.

FRANCINE: What things?

(The mystery man whispers to Francine.)

[Reception room]

MARTHA: What now? We've just gone round in a circle.

DOCTOR: We can't lead him outside. Come on, get in.

(They get into the sonic microfield manipulator chamber. The mutant is outside.)

[Chamber]

MARTHA: Are we hiding?

DOCTOR: No, he knows we're here. But this is his masterpiece. I'm betting he won't destroy it, not even to get at us.

MARTHA: But we're trapped.

DOCTOR: Well, yeah, that's a slight problem.

MARTHA: You mean you don't have a plan?

DOCTOR: Yes, the plan was to get inside here.

MARTHA: Then what?

DOCTOR: Well, then I'd come up with another plan.

MARTHA: In your own time, then.

(It is a tight squeeze for two inside.)

MARTHA: Hey!

DOCTOR: Sorry, sorry, sorry.

(He gets the sonic screwdriver out of his inside pocket.)

DOCTOR: Here we are.

MARTHA: What're you going to do with that?

DOCTOR: Improvise.

(He slides down to the floor and opens a panel, then starts working with the wires and processors he finds there.)

MARTHA: I still don't understand where that thing came from. Is it alien?

DOCTOR: No, for once it's strictly human in origin.

MARTHA: Human? How can it be human?

DOCTOR: Probably from dormant genes in Lazarus's DNA. The energy field in this thing must have reactivated them. And it looks like they're becoming dominant.

MARTHA: So it's a throwback.

DOCTOR: Some option that evolution rejected for you millions of years ago, but the potential is still there. Locked away in your genes, forgotten about until Lazarus unlocked it by mistake.

MARTHA: It's like Pandora's box.

DOCTOR: Exactly. Nice shoes, by the way.

(Outside, the mutant presses the big red button.)

MARTHA: Doctor, what's happening?

DOCTOR: Sounds like he's switched the machine on.

MARTHA: And that's not good, is it?

DOCTOR: Well, I was hoping it was going to take him a little bit longer to work that out.

MARTHA: I don't want to hurry you, but

DOCTOR: I know, I know. Nearly done.

MARTHA: Well, what're you doing?

DOCTOR: I'm trying to set the capsule to reflect energy rather than receive it.

MARTHA: Will that kill it?

DOCTOR: When he transforms, he's three times his size. Cellular triplication. So he's spreading himself thin.

MARTHA: We're going to end up like him!

DOCTOR: Just one more!

[Reception room]

(There is a big blast of energy that throws the mutant backwards. The machine stops and the Doctor and Martha come out.)

MARTHA: I thought we were going to go through the blender then.

DOCTOR: Really shouldn't take that long just to reverse the polarity. I must be a bit out of practice.

(A naked human man is lying face down on the floor.)

MARTHA: Oh, God. He seems so human again. It's kind of pitiful.

DOCTOR: Eliot saw that, too. This is the way the world ends. Not with a bang, but with a whimper.

[Outside the building]

(The ambulance men take away a figure covered in a red blanket.)

TISH: She's here. Oh, she's all right.

DOCTOR: Ah, Mrs Jones. We still haven't finished our chat.

(Francine slaps him hard across the face.)

FRANCINE: Keep away from my daughter.

MARTHA: Mum, what are you doing?

DOCTOR: All of the mothers, every time.

FRANCINE: He is dangerous. I've been told things.

MARTHA: What are you talking about?

FRANCINE: Look around you. Nothing but death and destruction.

(The ambulance leaves.)

MARTHA: This isn't his fault. He saved us, all of us!

LEO: And it was Tish who invited everyone to this thing in the first place. I'd say technically, it's her fault.

(Tish elbows Leo. There's a big crash, and the Doctor runs off to investigate.)

FRANCINE: Leave him.

(Martha shakes her head and follows the Doctor.)

TISH: Martha?

FRANCINE: Not you, too?

TISH: Sorry.

(Tish runs after Martha.)

[Street]

(The back of the ambulance is open, and only contains desiccated corpses.)

DOCTOR: Lazarus, back from the dead. Should have known, really.

(The Doctor scans with the screwdriver.)

MARTHA: Where's he gone?

DOCTOR: That way. The church.

TISH: Cathedral. It's Southwark Cathedral. He told me.

[Southwark Cathedral]

(Played by Wells Cathedral.)

MARTHA: Do you think he's in here?

DOCTOR: Where would you go if you were looking for sanctuary?

(They walk carefully up the nave to the altar. Lazarus is shivering behind it, wrapped in the red blanket.)

LAZARUS: I came here before, a lifetime ago. I thought I was going to die then. In fact, I was sure of it. I sat here, just a child, the sound of planes and bombs outside.

DOCTOR: The Blitz.

LAZARUS: You've read about it.

DOCTOR: I was there.

LAZARUS: You're too young.

DOCTOR: So are you.

(He laughs, then his body makes painful cracking sounds.)

LAZARUS: In the morning, the fires had died, and I was still alive. I swore I'd never face death like that again. So defenceless. I would arm myself, fight back, defeat it.

DOCTOR: That's what you were trying to do today?

LAZARUS: That's what I did today.

DOCTOR: What about the other people who died?

LAZARUS: They were nothing. I changed the course of history.

DOCTOR: Any of them might have done too. You think history's only made with equations? Facing death is part of being human. You can't change that.

LAZARUS: No, Doctor. Avoiding death, that's being human. It's our strongest impulse, to cling to life with every fibre of being. I'm only doing what everyone before me has tried to do. I've simply been more successful.

DOCTOR: Look at yourself. You're mutating! You've no control over it. You call that a success?

LAZARUS: I call it progress. I'm more now that I was. More than just an ordinary human.

DOCTOR: There's no such thing as an ordinary human.

(Lazarus convulses again.)

MARTHA: (sotto) He's going to change again any minute.

DOCTOR: (sotto) I know. If I can get him up into the bell tower somehow, I've an idea that might work.

MARTHA: (sotto) Up there?

LAZARUS: You're so sentimental, Doctor. Maybe you are older than you look.

DOCTOR: I'm old enough to know that a longer life isn't always a better one. In the end, you just get tired. Tired of the struggle, tired of losing everyone that matters to you, tired of watching everything turn to dust. If you live long enough, Lazarus, the only certainty left is that you'll end up alone.

LAZARUS: That's a price worth paying.

DOCTOR: Is it?

LAZARUS: I will feed soon.

DOCTOR: I'm not going to let that happen.

LAZARUS: You've not been able to stop me so far.

MARTHA: Leave him, Lazarus! He's old and bitter. I thought you had a taste for fresher meat.

DOCTOR: Martha, no.

(Lazarus lunges for Martha, who runs. Tish runs with her.)

MARTHA: What are you doing?

TISH: Keeping you out of trouble!

MARTHA: Doctor! The tower!

[Staircase]

(Martha and Tish run up the narrow spiral staircase. Lazarus has to keep stopping as he mutates.)

TISH: Did you hear that?

MARTHA: He's changed again. Keep moving. We've got to lead him up.

[Southwark Cathedral]

(The Doctor goes back to the transept, underneath the central tower, and looks for them.)

DOCTOR: Where are they? Martha?!

(Martha looks down from the passageway in the clerestory.)

MARTHA: Doctor!

DOCTOR: Take him to the top. The very top of the bell tower, do you hear me?!

MARTHA: Up to the top!

TISH: Martha.

MARTHA: Then what?

TISH: Martha, come on!

(The mutant is heading their way. The Doctor heads for the organ loft and gets out the screwdriver.)

[Organ loft]

DOCTOR: Hypersonic sound waves. Inspired.

(He sticks it into the power socket then starts pulling out stops.)

[Bell tower]

(Underneath the big Peter bell, played by Wells' Harewood bell.)

TISH: There's nowhere to go. We're trapped!

MARTHA: This is where he said to bring him.

TISH: All right, so then we're not trapped. We're bait.

MARTHA: He knows what he's doing. We have to trust him.

LAZARUS: Ladies.

MARTHA: Stay behind me. If he takes me, make a run for it. Head down the stairs. You should have enough time.

TISH: But

MARTHA: Just do it, Tish!

(The mutant tries to clamber across the gap under the bell, instead of going around the wooden frame.)

[Organ loft]

DOCTOR: I hope it's a good acoustic in here.

(The Doctor presses on both pedals and starts playing.)

[Bell tower]

(The mutant starts lashing with its tail, hitting Martha.)

TISH: Martha!

(Martha hangs on to the bottom of the wooden walkway, screaming.)

TISH: Hold on! Get away from her!

[Organ loft]

DOCTOR: We need to turn this up to eleven.

[Bell tower]

(The organ notes reverberate, hurting the mutant as well as Tish and Martha. Martha starts to lose her grip. The mutant falls to the cathedral floor below. The Doctor stops playing when he hears the crash, and goes to look. A naked man is lying on the flagstones amid a shower of broken wood. Martha's fingers slip just as Tish grabs her wrist.)

TISH: I've got you. Hold on.

[Organ loft]

DOCTOR: Martha?

[Bell tower]

MARTHA: I'm okay!

[Organ loft]

MARTHA [OC]: We're both okay!

[Bell tower]

MARTHA: Thanks.

TISH: It's your Doctor you should be thanking.

MARTHA: I told you he'd think of something.

TISH: He cut it a bit fine there, didn't he?

MARTHA: He always does. It's more fun that way.

TISH: Who is he?

MARTHA: He's, he's the Doctor.

[Southwark Cathedral]

(As the Doctor closes Lazarus' eyes, he turns back into an old man. Then he runs to meet Martha.)

MARTHA: I didn't know you could play?

DOCTOR: Oh, well, you know, if you hang around with Beethoven, you're bound to pick a few things up.

MARTHA: Hmm. Especially about playing loud.

DOCTOR: Sorry?

[Martha's home]

(The Doctor unlocks the Tardis.)

DOCTOR: Something else that just kind of escalated, then.

MARTHA: I can see a pattern developing. You should take more care in the future. And the past. And whatever other time period you find yourself in.

DOCTOR: It's good fun, though, isn't it?

MARTHA: Yeah.

DOCTOR: So, what do you say, one more trip?

MARTHA: No. Sorry.

DOCTOR: What do you mean? I thought you liked it.

MARTHA: I do, but I can't go on like this. One more trip. It's not fair.

DOCTOR: What're you talking about?

MARTHA: I don't want to be just a passenger anymore. Someone you take along for a treat. If that's how you still see me, I'd rather stay here.

DOCTOR: Okay, then. If that's what you want.

MARTHA: Right. But we've already said goodbye once today. It's probably best if you just go.

(She turns her back, but he just stands there.)

MARTHA: What is it?

DOCTOR: What? I said okay.

MARTHA: Sorry?

DOCTOR: Okay.

(Nodding towards the Tardis.)

MARTHA: Oh, thank you, thank you!

(They hug.)

DOCTOR: Well, you were never really just a passenger, were you?

(The Doctor and Martha go into the Tardis, and it dematerialises. The telephone rings.)

MARTHA [on machine]: Hi, I'm out. Leave a message.

FRANCINE [on machine]: Martha, it's your mother. Please phone me back. I'm begging you. I know who this Doctor really is. I know he's dangerous. You're going to get yourself killed. Please, trust me. This information comes from Harold Saxon himself. You're not safe!