WOMAN [OC]: When I was a child, my favourite story was about a man who lived forever, but whose eyes were heavy with the weight of all he'd seen. A man who fell from the stars.

[Desert]

(Night. A small satellite arrives, and its observer gets the instruction 'Terminate'. So he does.)

MAS: I knew you'd find me eventually.

(Kahler-Mas. Terminate.)

GUNSLINGER: Make peace with your gods.

MAS: Once they were your gods, too.

GUNSLINGER: Not any more.

(The man turns his back and reaches for his space weapon. The Gunslinger shoots him. We now see that he is a Cyborg with a cybernetic eye, a gun arm - literally - and a penchant for gunslinger clothes.)

MAN: Am I, am I the last one?

GUNSLINGER: There's one more. The Doctor.

[Mercy]

(The Old West of the USA. The Doctor stands just outside the entrance to Main Street, in front of a wooden frame with a cattle skull on it, a Keep Out sign and the residents count recently changed from 80 to 81.)

DOCTOR: Mercy. Eighty one residents.

(Now we see he is not alone.)

AMY: Look at this. It's a load of stones and lumps of wood. What is it?

DOCTOR: A load of stones and lumps of wood.

(The Gunslinger is watching from a distance.)

RORY: The sign does say Keep Out.

DOCTOR: I see Keep Out signs as suggestions more than actual orders, like Dry Clean only.

(They step over the load of stones and lumps of wood that circle the town and head down the street, towards the Grand Central Bank. The residents watch silently. An electric street lamp outside the Post Office sparks.)

DOCTOR: That's not right.

RORY: It's a street lamp.

DOCTOR: An electric street lamp about ten years too early.

RORY: It's only a few years out.

DOCTOR: That's what you said when you left your phone charger in Henry the Eighth's en-suite.

AMY: Doctor, er

DOCTOR: Anachronistic electricity, Keep Out signs, aggressive stares. Has someone been peeking at my Christmas list?

AMY: Doctor.

(He starts chewing on a toothpick and walks on.)

[Saloon]

(The piano playing and the conversations stop dead when our trio walk in. The Doctor goes to the bar.)

DOCTOR: Tea. But the strong stuff. Leave the bag in.

SADIE: What're you doing here, son?

DOCTOR: Son? You can stay.

(A Negro in a natty black suit speaks.)

PREACHER: Sir, might I enquire who you is?

DOCTOR: Of course. I'm the Doctor. This is

(Everyone stands up.)

DOCTOR: No need to stand. You see that? Manners. Oh, thank you.

(A man in a top hat starts measuring the Doctor.)

DOCTOR: But I don't need a new suit.

ABRAHAM: I'm the undertaker, sir.

(A younger man in a brown suit and bowler hat steps forward. I'm guessing at the character name. It might be Dockery instead.)

WALTER: I got a question. Is you an alien?

DOCTOR: Well, er, bit personal. It's all relative, isn't it? I mean, I think you're the aliens, but in this context, yes. Yes, I suppose I am.

[Mercy]

(The Doctor is hoisted up and carried out shoulder high.)

DOCTOR: Guys!

(Amy and Rory are dragged along too.)

AMY: Doctor! Put him down!

SADIE: Don't think we won't kill you.

RORY: Leave him alone!

DOCTOR: Rory, everything is completely under control. Guys, guys, guys.

(They throw the Doctor out of town. Literally.)

DOCTOR: Ow.

(When he turns around, they all point their revolvers at him. The Gunslinger suddenly appears in the distance.)

PREACHER: He's coming. Oh God, he's coming.

WALTER: Preacher, say something.

PREACHER: Our Father who art in heaven, hallowed be thy name.

(The Doctor turns around to see the Cyborg approaching by dimension jumps. He is scared.)

PREACHER: Thy kingdom come. Thy will be done.

(A mustachioed man fires a shot in the air. Ben Browder, everyone.)

ISAAC: You, bow tie. Get back across that line.

(He pulls back his coat to reveal a six pointed metal star with the word Marshal on it.)

ISAAC: Now.

(The Doctor steps over the rocks and wood, and the Cyborg stops then vanishes.)

WALTER: Isaac, he said he was a doctor. An alien doctor.

ISAAC: That a reason to hand him to his death?

WALTER: Isaac, it could be him.

ISAAC: You know it ain't.

(Isaac walks back down the street, nodding to Amy.)

ISAAC: Ma'am.

WALTER: Just letting him go like that? Be seeing you, boy.

[Marshal's Office]

DOCTOR: What was that outside?

ISAAC: The Gunslinger. Showed up three weeks back. We've been prisoners ever since. See that border line stretching round the town? Woke up one morning, there it was. Nothing gets past it, in or out. No supply wagons, no reinforcements. Pretty soon the whole town's going to starve to death.

RORY: But you let us in.

ISAAC: You ain't carrying any food. Just three more mouths to feed. We'll all die even sooner now.

DOCTOR: What happens if someone crosses the line?

(Isaac throws the Doctor a Stetson with a neat hole in it.)

DOCTOR: Ah, well, he wasn't a very good shot, then.

ISAAC: He was aiming for the hat.

DOCTOR: He shoots people's hats?

AMY: It was a warning shot.

DOCTOR: Ah, no, yes. I see. Hmm.

AMY: What does he want? Has he issued some kind of demand?

ISAAC: Says he wants us to give him the alien doctor.

AMY: But that's you. Why would he want to kill you? Unless he's met you.

RORY: And how could he know that we'd be here? (sotto) We didn't even know we'd be here.

AMY: We were aiming for Mexico. The Doctor was taking us to see the Day of the Dead Festival.

ISAAC: Mexico's two hundred miles due south.

DOCTOR: Well, that's what happens when people get toast crumbs on the console. Anyway, I think it's about time I met him, don't you?

ISAAC: Who?

DOCTOR: The chap outside said I could be the alien doctor, but you said I wasn't, so you already know who it is. Two alien doctors. We're like buses. Resident eighty one, I presume, so beloved by the townsfolk he warranted an alteration to the sign. Probably because he rigged up these electrics, and I'm guessing he's in here, because if half the town suddenly wanted to throw me to my death, this is where I'd want to be.

ISAAC: I don't know what you

(The man in the cell throws back his blanket. He has a curved mark down the left side of his face, similar but not the same as Mas had.)

JEX: Isaac, I think the time for subterfuge has passed. Good afternoon. My name is Kahler-Jex. I'm the doctor.

(The Gunslinger watches the town from a distant ridge.)

DOCTOR: The Kahler. I love the Kahler. They're one of the most ingenious races in the galaxy. Seriously, they could build a spaceship out of Tupperware and moss.

AMY: All right. How did you get here?

JEX: My craft crashed about a mile or so out of town. I would have died if Isaac and the others hadn't pulled me from the wreckage.

DOCTOR: And you stayed, as their doctor.

JEX: On my world I was a surgeon, so it seemed logical. And it gave me an opportunity to repay my debt to them.

ISAAC: Listen to him. Talking like it was nothing. Tell them about the cholera.

JEX: Now, Isaac, I'm sure our guests are

ISAAC: Two years after he arrived, there was an outbreak of cholera. Thanks to the doc here, not a single person died.

JEX: A minor infection we'd found a treatment for centuries ago.

ISAAC: No, no, what, what do you call them? The electrics?

JEX: Using my ship as a generator, I was able to rig up some rudimentary heating and lighting for the town.

DOCTOR: So why does the Gunslinger want you?

ISAAC: It don't matter.

DOCTOR: I'm just saying, if we knew that

ISAAC: America's the land of second chances. We called this town Mercy for a reason. Others, some round here, don't feel that way.

JEX: Now, Isaac, we've discussed this.

ISAAC: People whose lives you've saved are suddenly saying we should hand you over.

JEX: They're scared, that's all. You can hardly blame them.

ISAAC: Them being scared scares me. War only ended five years back. That old violence is still under the surface. We give up Doc Jex, then we hand the keys of the town over to chaos.

DOCTOR: Did you try to repair your craft? Surely someone with your skills

JEX: It really was very badly damaged.

DOCTOR: We evacuate the town. Our ship's just over the hills, room for everyone. I'll pop out, bring it back here, Robert's your uncle.

AMY: Really? Simple as that. No crazy schemes, no negotiations.

DOCTOR: I've matured. I'm twelve hundred years old now. Plus I don't want to miss The Archers.

AMY: Oh, so you're not even a tiny bit curious?

DOCTOR: Why would I be curious? It's a mysterious space cowboy assassin. Curious? Of course I'm not curious.

ISAAC: Son? You've still got to get past the Gunslinger. How you going to do that?

(The Doctor puts on the Stetson.)

DOCTOR: With a little sleight of hand.

[Desert]

(Isaac and Rory run across the parched waste.)

ISAAC: You okay?

RORY: I'm fine, yes.

ISAAC: Keep moving. Next time, you get to wear Jex's clothes.

(The Gunslinger spots them, but his computer tells him there is an 87% chance of injury to innocent, disengage, so he does.)

[Mercy]

DOCTOR: Can I borrow your horse, please? It's official Marshal business.

PREACHER: He's called Joshua. It's from the Bible. It means the Deliverer.

DOCTOR: No, he isn't. I speak horse. He's called Susan, and he wants you to respect his life choices.

(The Doctor gallops out of town.)

[Cliff face]

(Isaac is leading Rory in front of a cliff when the rock explodes between them.)

RORY: Er, I think he's seen us.

ISAAC: This way.

[Marshal's Office]

AMY: When this is all done, do you want us to take you home?

JEX: Thank you, but I've already given everything I have to the Kahler. My skills, energy, all that was good in me. Here, I could start afresh. I could remember myself and help people. That's all I ever wanted to do, end suffering.

AMY: Here.

(She puts Isaac's coat over Jex's shoulders.)

JEX: You're a mother, aren't you.

AMY: How did you know?

JEX: There's kindness in your eyes. And sadness, but a ferocity too.

AMY: Life's not exactly straight forward.

JEX: It seldom is.

AMY: And what about you? Are you a father?

JEX: Yes. In a way, I suppose I am.

[Ridge]

ISAAC: So, we're waiting till the Doctor comes to pick us up in your ship.

RORY: Yes, I know. I was there when we agreed it.

ISAAC: Yeah, I said that more for my benefit than yours.

[Desert]

(The Doctor is galloping down the road when he slows up.)

DOCTOR: Whoa, whoa, whoa, whoa, whoa. Yes, I know we're in a hurry. I just want to check something out. Two ticks.

(He dismounts.)

DOCTOR: There's something niggling me. Yes, yes, it could be important. Oi, don't swear.

(He rummages in the dust and finds the shiny power cable that connects Jex's ship to the town. Jex notices the light in the office flickering. The Doctor rides on until he reaches the source of the power covered in a tarpaulin.)

DOCTOR: Whoa, whoa, whoa. Yes, I wear a Stetson now.

(The Doctor uncovers the gleaming white egg-shaped object.)

DOCTOR: Yes, a good point, Susan. Where is the damage?

(The Gunslinger stands on the ridge above Isaac and Rory. Target located. Terminate. Meanwhile, the Doctor is trying to get into Jex's ship. His sonic screwdriver sets off an alarm then a hatch opens. The Gunslinger hears it. Kahler Alarm Detected. It powers down its gun and goes to investigate.)

[Mercy]

(The alarm can even be heard in town.)

JEX: That's the alarm on my ship.

AMY: Maybe the Doctor wants to get it working again?

JEX: But that wasn't the plan. He's not following the plan.

AMY: Welcome to my world.

[Jex's spaceship]

(The Doctor drops straight down into the pilot seat.)

COMPUTER: Security breach. You have ten seconds to enter the pass code.

(The hatch closes and the Doctor starts waving the sonic screwdriver around.)

COMPUTER: Or this vehicle will self-destruct. Thank you for choosing Abarakas Security software. Incinerating intruders for three centuries. Nine, eight, seven. Self-destruct overridden.

DOCTOR: This is an awful lot of security for a titchy spacecraft.

COMPUTER: Awaiting command.

DOCTOR: Tell me everything you can about the Gunslinger.

COMPUTER: File not found. Please choose from Technical Specifications, Flight Recorder, Personal Files, Maps and Charts.

DOCTOR: Personal files of Doctor Kahler-Jex.

(Experimental Cyborg Program Military Science Unit.)

JEX [OC]: Names of deceased subjects can be found on the drop down menu.

(We hear the screams of the subjects but only see scrolling text reflected on the Doctor's face.)

[Marshal's Office]

(Amy enters to discover Jex pointing a revolver at her head.)

JEX: I'm sorry, Amy. He really should have followed the plan.

[Desert]

(The Doctor pops out of the spaceship to find the Gunslinger is right behind him. He ducks back inside briefly then out again.)

DOCTOR: Don't shoot, don't shoot, don't shoot. I know who you are, and who Jex is, too.

(The Gunslinger powers down his weapon.)

DOCTOR: Now, what I don't understand is why you haven't just walked into town and killed him.

GUNSLINGER: People will get in the way.

DOCTOR: You want justice, you deserve justice, but this isn't the way. We can put him on trial

GUNSLINGER: When he starts killing your people, you can use your justice.

[Marshal's Office]

JEX: Isaac says he doesn't care about my past, but things may have been uncovered that even he might struggle to forgive, so it's best we beat a hasty retreat.

AMY: We? I'm coming with you?

JEX: It's unlikely the Gunslinger will shoot if I'm with you. As far as I can tell, he's programmed to take innocent lives only if absolutely necessary.

AMY: Oh, well, colour me reassured.

(Jex opens the door and gets a gun in the back of his neck.)

ISAAC: Doc? What are you doing?

[Desert]

GUNSLINGER: No more warning shots. I'll kill the next person to step over that line. Make sure it's Jex.

[Marshal's Office]

JEX: It was stupid of me, I realise that now. I just thought I'd put you all in enough danger. Perhaps if I left

(The Doctor enters.)

DOCTOR: He's lying. Every word, every thing he says, it's all lies. This man is a murderer.

JEX: I am a scientist.

DOCTOR: Sit down. Sit down! Tell them what you are.

JEX: What am I? A war hero.

ISAAC: Okay, somebody want to tell me what is going on?

DOCTOR: The Gunslinger is a Cyborg.

ISAAC: A what?

DOCTOR: Half man, half machine. A weapon. Jex built it. He and his team took volunteers, told them they'd been selected for special training, then experimented on them, fused their bodies with weaponry, and programmed them to kill.

ISAAC: Okay. Why? Why would you do that, Doc?

JEX: We'd been at war for nine years. A war that had already decimated half of our planet. Our task was to bring peace, and we did. We built an army that routed the enemy and ended the war in less than a week. Do you want me to repent, to beg forgiveness for saving millions of lives?

DOCTOR: And how many died screaming on the operating table before you had found your advantage?

JEX: War is another world. You cannot apply the politics of peace to what I did. To what any of us did.

RORY: What happened then? How come you're here?

JEX: When the war ended we had the Cyborgs decommissioned, but one of them must have got its circuitry damaged in battle. It went offline and began hunting down the team that created it until just two of us were left. We fled, and our ships crashed here.

RORY: So, what do we do with Jex?

ISAAC: What do we do with him?

RORY: Yeah. I mean, he's a war criminal.

ISAAC: No, he's the guy that saved the town from cholera, the guy that gave us heat and light.

AMY: Look, Jex may be a criminal and yeah, kind of creepy

JEX: And still in the room.

AMY: But I think we should put aside what he did and find another solution.

RORY: Another solution? It's him or us.

AMY: When did we start letting people get executed? Did I miss a memo? Doctor, tell him.

DOCTOR: Hmm? Yes. I don't know. Whatever Amy said.

JEX: Looking at you, Doctor, is like looking into a mirror, almost. There's rage there, like me. Guilt, like me. Solitude. Everything but the nerve to do what needs to be done. Thank the gods my people weren't relying on you to save them.

DOCTOR: No. No, but these people are. Out! Out! Out!

(Rory stops Amy at the door.)

AMY: Oh, you're really letting him do this?

RORY: Save us all? Yeah, I really am.

[Mercy]

JEX: No!

(The Doctor pushes Jex along the street.)

DOCTOR: Go on.

(The townsfolk follow Isaac to see the Doctor push Jex over the boundary.)

DOCTOR: Get over, and don't come back.

(The Doctor takes a gun from a man's holster and points it at Jex as he tries to return.)

JEX: You wouldn't.

DOCTOR: I genuinely don't know.

ISAAC: Doctor. Doctor.

(Amy gets another gun and fires in the air.)

AMY: Let him come back, Doctor.

DOCTOR: Or what? You won't shoot me, Amy.

AMY: How do you know? Maybe I've changed. I mean, you've clearly been taking stupid lessons since I saw you last.

(Her gun fires again.)

AMY: I didn't mean to do that.

(So Isaac fires to get everyone's attention.)

ISAAC: Everyone who isn't an American, drop your gun.

DOCTOR: We can end this right now. We could save everyone right now.

AMY: This is not how we roll, and you know it. What happened to you, Doctor? When did killing someone become an option?

DOCTOR: Jex has to answer for his crimes.

AMY: And what then? Are you going to hunt down everyone who's made a gun or a bullet or a bomb?

DOCTOR: But they coming back, don't you see? Every time I negotiate, I try to understand. Well, not today. No. Today, I honour the victims first. His, the Master's, the Dalek's, all the people who died because of my mercy!

AMY: You see, this is what happens when you travel alone for too long. Well, listen to me, Doctor. We can't be like him. We have to be better than him.

DOCTOR: Amelia Pond. Fine, fine. We think of something else. But frankly, I'm betting on the Gunslinger.

(The Doctor gives his gun back and holds out his hand.)

DOCTOR: Jex, move over the line. Now.

(Because the Gunslinger is right behind him. Jex turns around.)

GUNSLINGER: Make peace with your gods.

JEX: Kahler-Tek, isn't it? I remember all your names, even now. I'll never hurt anyone again. I'm even helping people here.

GUNSLINGER: Last chance. Make peace with your gods.

ISAAC: No!

(Isaac pushes Jex out of the way and takes the Gunslinger's shot instead.)

DOCTOR: Isaac. Isaac. Isaac. It's okay, it's okay. We can get you to Jex's surgery. He can save you.

(Life Signs Deteriorating.)

ISAAC: Listen to me. You've got to stay. You've got to look after everyone.

DOCTOR: It won't come to that, Isaac.

ISAAC: Protect Jex. Protect my town. You're both good men. You just forget it sometimes.

(Isaac dies, handing on his Marshal's badge. The Doctor stands up and pins it on his jacket.)

DOCTOR: Take Jex to his cell. If anything happens to him, you'll have me to answer to.

(Jex is escorted away. The Doctor speaks to the Gunslinger.)

DOCTOR: This has gone on long enough.

GUNSLINGER: You are right. You've got until noon tomorrow. Give him to me or I'll kill you all.

(The Gunslinger vanishes.)

AMY: Oh, my god. You're the Marshal.

DOCTOR: Yeah. And you're the Deputy.

[Marshal's Office]

(Night. Someone hammers on the door.)

DOCTOR: Come in.

PREACHER: Marshal. Ma'am. Fella. You need to come outside.

DOCTOR: Why, what's wrong?

PREACHER: Just come outside. And you should put that on.

(The gun belt.)

[Outside the Marshal's Office]

(The townsfolk have gathered.)

DOCTOR: What's going on?

WALTER: He in there? Leave the keys and take a walk. By the time you get back, this'll all be done.

DOCTOR: I promised Isaac I'd protect him.

WALTER: Protecting him got Isaac dead. Tomorrow, it's going to be us all, dead.

DOCKERY: We thought Isaac was right to fight, but it's different now. We've got to say, all right we lost, and give that thing what it wants.

SADIE: What it wants is to kill our friend.

WALTER: We don't got any ill feeling towards the Doc. We just thinking about our families. Hand him over and we all safe again.

DOCTOR: You know I can't do that.

WALTER: We got us a problem.

DOCTOR: Please don't do this.

WALTER: Why, reckon you're quicker than me?

DOCTOR: Oh, certainly not, but this? Lynch mobs? A town turning against itself? This is everything Isaac didn't want.

(Walter draws his gun and cocks it.)

DOCTOR: How old are you?

WALTER: Nearly nineteen.

(The Doctor is slowly walking forward.)

DOCTOR: That's eighteen, then. Too young to have fought in the war, so I'm guessing you've never shot anyone before, have you?

WALTER: First time for everything.

DOCTOR: But that's how all this started. Jex turned someone into a weapon. Now that same story's going to make you a killer, too. Don't you see? Violence doesn't end violence, it extends it, and I don't think you want to do this. I don't think you want to become that man.

WALTER: There's kids here.

DOCTOR: I know, who I can save if you'll let me.

WALTER: He really worth the risk?

DOCTOR: Don't know. But you are.

(Walter lowers his gun and walks away. The crowd disperses.)

DOCTOR: Frightened people. Give me a Dalek any day.

[Marshal's Office]

(The Doctor removes the gun belt.)

ABRAHAM: Fresh coffee, Marshal. For what it's worth, I know you're going to save us. Isaac made you Marshal for a reason, and if you're good enough for him, you're good enough for me. Reckon you should know that.

DOCTOR: Thank you.

(Abraham continues to take his measurements.)

DOCTOR: Oi. Get out of it.

(Abraham leaves.)

JEX: Let me guess. The good folk of Mercy wanted me to take a little stroll into the desert. You could turn a blind eye. No one would blame you. You'd be a hero.

DOCTOR: But I can't, can I. Because then Isaac's death would mean nothing. Just another casualty in your endless bloody war. Do you want me to hand you over? Is that what you want? Do you even know?

JEX: You think I'm unaffected by what I did? That I don't hear them screaming every time I close my eyes? It would be so much simpler if I was just one thing, wouldn't it? The mad scientist who made that killing machine, or the physician who's dedicated his life to serving this town. The fact that I'm both bewilders you.

DOCTOR: Oh, I know exactly what you are, and I see this reformation for what it really is. You committed an atrocity and chose this as your punishment. Don't get me wrong, good choice. Civilised hours, lots of adulation, nice weather, but, but justice doesn't work like that. You don't get to decide when and how your debt is paid.

JEX: In my culture, we believe that when you die your spirit has to climb a mountain carrying the souls of everyone you wronged in your lifetime. Imagine the weight I will have to lift. The monsters I created, the people they killed. Isaac, he was my friend. Now his soul will be in my arms, too. Can you see now why I fear death? You want to hand me over. There's no shame in that. But you won't. We all carry our prisons with us. Mine is my past. Yours is your morality.

DOCTOR: We all carry our prisons with us. Ha!

[Chapel]

(Getting close to high noon. Marshal Doctor is out on the street in front of the Bank. The townsfolk have gathered together to pray.)

PREACHER: Help me. Help me to

(Inside the Marshal's office, Amy and Jex hear the whoosh of the Gunslinger dimension-shifting towards town. The clock strikes 12 as he steps across the barrier. When it finishes striking, the Gunslinger raises his weapon. The Doctor brandishes the sonic screwdriver, disrupting his systems and ruining his aim. Several windows and the Bank clock suffer as the Doctor runs away.)

[Marshal's Office]

AMY: Ready?

(She unlocks the cell.)

[Mercy]

RORY: Ready?

(He and Walter have replicas of Jex's identifying mark on their faces. So do several other men. They run, confusing the Gunslinger. Error: Invalid Visual Match.)

GUNSLINGER: Disengage. It's a trick.

[Chapel]

(The Gunslinger stomps past.)

PREACHER: (sotto) Save us, O Lord.

(A little girl gets up and knocks over some hymnals. The Gunslinger hears it and blasts his way in. The people start screaming.)

[Mercy]

(Jex hesitates at the sound.)

DOCTOR: Go! Just go! I can't save them while you're here.

(The Gunslinger looks into the little girl's eyes, and leaves the Chapel. Jex runs out of town and back to his little spaceship.)

[Jex's spaceship]

COMPUTER: Nine, eight, seven. Self destruct overridden.

[Mercy]

GUNSLINGER: Deactivate automatic targeting. Switch to manual.

(He locates the Doctor hiding around the corner of a building. He's got the Jex mark, too.)

DOCTOR: Right.

GUNSLINGER: Where is he?

DOCTOR: He's gone.

GUNSLINGER: Where? Answer me.

DOCTOR: Away from here. Look up. Any second now you'll see the vapour trail of his ship. This is their home, not the backdrop for your revenge. Lookup, go after him, take this battle away from

JEX [OC]: Kahler-Tek.

[Jex's spaceship]

JEX: Kahler-Tek.

[Mercy]

GUNSLINGER: Jex. Coward.

[Jex's spaceship]

GUNSLINGER [OC]: Where are you?

JEX: I'm in my ship.

[Mercy]

DOCTOR: What are you doing? Just go!

JEX [OC]: Where are you from?

[Jex's spaceship]

JEX: Where on Kahler?

[Mercy]

DOCTOR: Now? You're asking him this now?

GUNSLINGER: Gabriah.

[Jex's spaceship]

JEX: I know it. It's beautiful there. When this is over, will you go back?

GUNSLINGER [OC]: How can I?

[Mercy]

GUNSLINGER: I am a monster now.

[Jex's spaceship]

JEX: So am I.

[Mercy]

DOCTOR: Just go! Finish this!

GUNSLINGER: I'll find you. If I have to tear this universe apart, I will find you.

[Jex's spaceship]

JEX: I don't doubt that.

[Mercy]

JEX [OC]: You'll chase me to another planet

[Jex's spaceship]

JEX: And another race will be caught in the cross-fire.

[Mercy]

GUNSLINGER: Face me!

[Jex's spaceship]

COMPUTER: Count down to self-destruct resumed.

[Mercy]

GUNSLINGER: Face me!

JEX: No. You've killed enough.

[Jex's spaceship]

JEX: I'm ending the war for you, too.

COMPUTER: Count down to self-destruct

[Mercy]

COMPUTER [OC]: Resumed.

DOCTOR: What's going on?

COMPUTER [OC]: Ten.

[Jex's spaceship]

DOCTOR [OC]: The count down.

[Mercy]

DOCTOR: What's going on? Jex!

JEX [OC]: Thank you, Doctor. I have to face

[Jex's spaceship]

JEX: The souls of those I've wronged.

COMPUTER: Five

JEX: Perhaps they will be kind.

COMPUTER: Three, two, one, zero.

(The white egg goes KaBOOM.)

[Mercy]

(The black smoke rises above the roof tops. The Gunslinger bows his head.)

GUNSLINGER: He behaved with honour at the end. Maybe more than me.

DOCTOR: We could take you back to your world. You could help with the reconstruction.

GUNSLINGER: I will walk into the desert and self-destruct. I'm a creature of war. I have no role to play during peace.

DOCTOR: Except maybe to protect it.

(Later, the Doctor runs out of the Marshal's Office. The Tardis is parked in the middle of the street.)

DOCTOR: Okay, so, our next trip. Oh! You know all the monkeys and dogs they sent into space in the fifties and sixties? You will never guess what really happened to them.

AMY: Could we leave it a while? Our friends are going to start noticing that we're aging faster than them.

DOCTOR: Another time? No worry.

(Amy waves farewell to Walter and the Preacher, then she and Rory go into the Tardis. The Doctor and Walter do a mock quick draw, which the Doctor wins, then he goes inside and the Tardis dematerialies. The little girl goes out of town and looks up to a distant ridge where the Gunslinger is standing guard over the town.)

WOMAN [OC]: By the time the Gunslinger arrived, the people of Mercy were used to the strange, the impossible. Where he came from didn't matter. As a man once said, America is a land of second chances. Do I believe the story? I don't know. My great-grandmother must have been a little girl when he arrived. But next time you're in Mercy, ask someone why they don't have a Marshal or Sheriff or policeman there. We've got our own arrangement, they'll say, then they'll smile like they got a secret. Like they've got their own special angel watching out for them. Their very own angel who fell from the stars.