DOCTOR [OC]: Planet Earth, early in the third decade of the 21st century. Population, seven billion. Seven billion lives, separate and connected, from the depths of the oceans to the edge of the atmosphere.

[Soyuz capsule]

(Hurtling through the atmosphere.)

ADAM: Soyuz to Control. We have automatic system failure.
CONTROL [OC]: Copy that, Soyuz. Can you switch to ballistic descent and maintain trajectory?
ADAM: Negative. I'm way off course. DMP's failed, and we have to deploy the parachute. (sparks flying) Ah! Control, do you copy?

(Heatshield is glowing.)

[Supermarket]

(A person crashes through a pile of bottled Garwell water and runs between the shelves, chased by another man, who tackles him by the checkouts.)

JAKE: You, my friend, are under arrest. You do not have to say anything, but anything you do say may seriously aggravate me.
JOYCE: Jake, what are you doing?
JAKE: Nailed him.

(Later, the shoplifter limps out of the store.)

JAKE: I can't believe you're letting him walk away.
JOYCE: You can't go round rugby-tackling kids like that. You're not a police officer, Jake.
JAKE: Yes, I am. I'm just...on a break. Getting my head straight.
JOYCE: This really isn't working out, is it?

[Peru]

(Two women jump out of the back of a pick-up truck.)

GABRIELA: Obrigada.

(Filming themselves on a phone.)

GABRIELA: Close your eyes.
JAMILA: Why?
GABRIELA: Trust me. You're gonna love this. This is the most beautiful river in the world. Okay.

(She opens her eyes. The banks of the river are covered in plastic rubbish, and flies are everywhere.)

JAMILA: Is this a joke?
GABRIELA: It's wrecked.

(Masses of birds circle overhead.)

GABRIELA: I don't know what happened. Three years ago, this was paradise.
JAMILA: Gabriela, there's no way in hell we're camping here tonight.

[Tent]

(Gabriela snores.)

JAMILA: Every time.

(Sound of wings nearby.)

JAMILA: Oh!

(She leaves the tent and stumbles in the rubbish.)

JAMILA: Urgh.

(The birds are still circling in the night sky. Something dives towards her, she screams.)

[Bar]

(Jake is drowning his sorrows.)

TV: Another win for Liverpool has seen them increase pressure on their title rivals Manchester City. Now, I'm just hearing that we have some breaking news.

(BBC News shows a shot of the space capsule burning up in the atmosphere.)

JAKE: Mate, can you turn that up?

(Space Agency confirms crash.)

TV: A statement just issued by the European Space Agency says they're still unable to confirm whether the British astronaut Adam Lang managed to evacuate his descent module safely after it veered off course and crashed into the Indian Ocean earlier today. Although search and rescue teams continue to trawl the waters, the agencies say they are now treating Adam Lang as missing, presumed dead. There are tributes for Mister Lang on social media and his family have asked for privacy at what they say is a difficult time.

(A text message arrives on Jake's phone from +85207700900781 - Help me. He replies, Who is this? Answer - Adam. Find me. Then a location map of Hong Kong.)

[Peru]

GABRIELA: Jamila!

(A black bird drops out of the sky.)

GABRIELA: What the hell? That's weird.
RYAN: Hey! Don't touch it. Something's wrong with the birds.

[Hong Kong]

PHONE: You have arrived at your destination.

(Jake presses a door buzzer. No answer, so he tries to kick the door down.)

YASMIN: I don't think they're too keen on visitors.
GRAHAM: Come on, son. Fists down, There's a good lad. Now, perhaps you'd like to tell us why you're so interested in that door.
JAKE: DI Jake Willis. I've reason to believe there may be a missing person inside that building.
YASMIN: Bit out of your jurisdiction, this.
JAKE: Sorry, who are you?
YASMIN: We're the people with a nice big set of skeleton keys.

(She unlocks the reinforced door and enters. Graham gestures for Jake to go in.)

[Madagascar]

(A prefab building is just above the high water mark.)

ARAMU: Good morning, Suki. Sleep in?
SUKI: One day I will get here before you.
ARAMU: But I'm always ready for work. Especially work like this.

(Running along the beach.)

DOCTOR: Need some help over here!

(There's a person in the water. The Doctor throws off her coat and goes in to grab an arm as Aramu and Suki get there.)

DOCTOR: Hi! Why is it always the big lads that need rescuing? Ah, thanks. I normally have my mates with me. I gave them all errands.

[Peru]

GABRIELA: If you touched Jamila...
RYAN: Hey, I don't even know who Jamila is.
GABRIELA: She vanished. And you are the only other person out here.
RYAN: Okay. But I swear I haven't seen her. I'm here because of what's wrong with the birds.
GABRIELA: You think I'll buy that?
RYAN: You should, because it's the truth. Look, I'm not armed. There's nothing in me bag. Check yourself if you don't believe me. How long has she been gone?
GABRIELA: I last saw her before I went to sleep last night. Stand still.

(She finishes going through Ryan's rucksack then frisks him.)

RYAN: Have you tried her phone?
GABRIELA: Of course I've tried her phone. I tried her on everything. I just messaged some contacts on Reddit to access emergency services and satellites. Ooo. You work out?
RYAN: I do a lot of running.
GABRIELA: I'm Gabriela. I'm guessing you know that.
RYAN: No.
GABRIELA: Two Girls Roaming. The travel vlog. That's me and Jamila.
RYAN: Sorry. Bit behind. I do a fair bit of travelling myself. I'm Ryan. Need to take that bird. These markings, they're not natural.

(He covers the bird with sacking before picking it up.)

GABRIELA: What are you doing?
RYAN: Birds are falling out of the sky. I'm trying to find out the reason.

(Gabriela's phone pings.)

RYAN: That her?
GABRIELA: No. But someone's found out there was an emergency call-out this morning. One mile away. Ambulancia.

[Warehouse]

JAKE: So who are you? Interpol? Did the ESA send you?
GRAHAM: ESA?
JAKE: European Space Agency. To find their missing astronaut?
YASMIN: Your missing person's an astronaut?
JAKE: Adam Lang. Equipment failure coming back from the International Space Station. It's all over the new... You're not even looking for him, are you?
YASMIN: There's some very unusual energy patterns coming from this building. We're under instructions to find out why.
JAKE: A man's gone missing and nobody's doing anything to find him.
GRAHAM: Apart from you. The police.
JAKE: Yeah.

(Someone in a rubber suit and gas mask is watching them.)

[Madagascar]

DOCTOR: Right. Let's put him down.
ARAMU: This is a US naval uniform.
SUKI: What's he doing here?
DOCTOR: A US submarine went missing in the Indian Ocean. I've been checking the tide patterns for survivors. I'm the Doctor, by the way.
ARAMU: Aramu and Suki.
DOCTOR: Nice to meet you both. You live here?
SUKI: Work here. That's my lab. We could get him inside and...
ZACH: (gasps) Help me.
DOCTOR: It's all right. You're safe.
ZACH: No. No, I'm not.
DOCTOR: What's your name?
ZACH: Zach Olson. There was an impact. Our captain tried to raise the sub, but it was too late. It was already inside.
DOCTOR: What was already inside, Zach?
ZACH: Oh, no.
ARAMU: What's on his hand?

(Whatever it is, it crackles and is spreading.)

ZACH: Oh, no! No! No!

(It covers his face then he explodes into a shower of dust.)

DOCTOR: Okay. So with the understanding that was pretty alarming, don't be overly alarmed.
SUKI: His body just disintegrated.
DOCTOR: Yes. Poor man.
SUKI: How is that even possible?
DOCTOR: I don't know. There's a connection between all these things, I just... Argh, I just can't see it yet.
ARAMU: Between what things?
DOCTOR: A missing submarine, a dead naval officer off the coast of Madagascar, birds going haywire in Peru, and active alien tech in Hong Kong. There's also a talking cat in Ontario, but I've ruled him out for now. What?
ARAMU: You just said...alien.

[Hospital San Pedro]

GABRIELA: This is the hospital the ambulance brought her to.

(It looks deserted.)

RYAN: Hello? Hello?

(They wander the corridors.)

GABRIELA: Where are all the staff?

(Dead bird on the floor.)

RYAN: Another one in here.
GABRIELA: What are you doing?
RYAN: The same as the river.

(A door bangs. They walk into an area where the lights are flickering. Black and yellow tape crosses the corridor.)

GABRIELA: Hey! The whole point of quarantine is not going in where it says quarantine.
RYAN: Do you want to find her or not?

(They push open the doors to see a figure covered in a sheet.)

GABRIELA: Tell me that's not her.

(Ryan pulls back the sheet.)

GABRIELA: Jamila.

(With the same stuff as Olsen on her face.)

RYAN: I'm sorry.
GABRIELA: Melhor amiga.

(Ryan uses his commdot.)

RYAN: Doctor? I found something that you wanna see.
GABRIELA: Who are you talking to? How are you calling a doctor?
RYAN: You've seen these markings before?

(Gabriela touches Jamila's face and her eyes open - they are blank white.)

GABRIELA: Jamila!
RYAN: Hey, get away from her.

(The TARDIS materialises. Jamila keeps arching her back.)

GABRIELA: No! She's alive! Jamila, (in Portuguese) calm down. Everything is all right.
RYAN: I don't think that's alive.
GABRIELA: We have to help her!
DOCTOR: No, Ryan's right. She's not alive. Whatever caused her death seems to still be attacking her body.
GABRIELA: Who are you?
RYAN: Doctor, her face.
DOCTOR: Yeah. I've just seen the same thing on a naval officer in Madagascar.

(Jamila's skin is finally covered, and she explodes into dust.)

GABRIELA: Jamila.
DOCTOR: Same as Zach on the beach.
GABRIELA: No, no, no, this can't be happening.
RYAN: Hey, it's okay.
GABRIELA: No, it's not!
DOCTOR: Two identical deaths on two different continents. It's even more dangerous than I thought, and it's spreading. Which could mean... Have you heard from Yaz and Graham?

[Warehouse]

(Graham's gizmo bingles.)

GRAHAM: Hey. Hey. Whatever is giving off those weird readings is on the other side of that wall. Is on the other side of this door.
YASMIN: You're welcome. (tries the door) Locked from the inside.
GRAHAM: Maybe if we went round the other way.

(Jake kicks the door down. Did this guy work with DCI Gene Hunt?)

JAKE: Chat, chat, chat, chat, chat.

(They go through the door.)

JAKE: What the hell is all this?
YASMIN: Exactly what we've been looking for.

(She touches the humanoid figure icon on an alien control panel, and the spacesuited figure hooked up to various machines is lit up.)

JAKE: Adam? Adam! I told you he was here. I'm gonna get this stuff off him.
YASMIN: Wait! Not until we know what all this stuff is doing.
GRAHAM: No, Yaz is right. You can't just go blundering in. You could end up killing him.
JAKE: How long's that going to take?
YASMIN: We've been in this room as long as you. (commdot) Doctor, we found the source of the energy. Plus a kidnapped astronaut.
JAKE: Adam? Can you hear me? It's Jake. I'm here. I'm here for you. I'm here.
ADAM: Get out.
JAKE: What?
ADAM: They'll come.

(Two figures in loose rubber suits and gas masks, and carrying very alien guns, burst in and start firing.)

YASMIN: Get down!
GRAHAM: Unplug him and get him out!
JAKE: You just said that wasn't safe!
GRAHAM: The situation's changed. Get him out! Yaz, what are you doing?

(Yasmin grabs the control panel.)

YASMIN: Oi! Guns down, or I'll trash it. Hesitation. Must be valuable.
GRAHAM: Yaz, we're out. Come on.

(The shooting starts again. Jake is helping Adam.)

GRAHAM: Lads, keep going. They're right behind us.
ADAM: You came.
JAKE: Of course I came.
YASMIN: Who are you with? Can you get back-up?
ADAM: Back-up? Why would he have back-up?
GRAHAM: He's a copper!
ADAM: Ex-copper.
GRAHAM + YASMIN: What?
JAKE: Can we not do this now?
YASMIN: Look out!

(Jake kicks a figure in the stomach, grabs its weapon and shoots it.)

JAKE: Down!
GRAHAM: Look out!

(And shoots one coming up behind them.)

JAKE: I'm on a sabbatical.
GRAHAM: That's okay. So's she.
YASMIN: Except I don't go around announcing I'm police.
ADAM: Never believe anything he says.
GRAHAM: Mate, he's just come halfway round the world to rescue you.
JAKE: Thank you!
DOCTOR: I scanned this building for life signals before I sent you here, so why didn't these register?
YASMIN: Doctor?
DOCTOR: Could be the suit blocking the scan.
JAKE: Is she with you?
DOCTOR: Oh. Can't get the breathing apparatus off to see their face. Non-terrestrial. Same as the weapon.

(She takes it off Jake and throws it aside.)

JAKE: So who are you?
DOCTOR: I'm the back-up. Oh. Adam Lang. Famous British astronaut. Famous missing British astronaut. Glad you're safe. How are you feeling?
ADAM: Terrible.
DOCTOR: Yeah, you look it. Hadn't factored you into this. Focused too much on that cat. This way. I'll introduce you to Gabriela once we're inside. She's having a tough time as well.
JAKE:Inside where?
GRAHAM: Probably best you see for yourself.

[TARDIS]

GABRIELA: Is it like, er, an optical illusion?
RYAN: I really don't know. How long have you and Jamila known each other?
GABRIELA: Five years. I don't know what I'm going to do now.
RYAN: You'll get through it.
GABRIELA: Cos you've known me for how many hours?
RYAN: We're going to find out what happened, and we're going to put it right. So you really don't believe this thing travels?

[Hong Kong]

(Gabriela looks out into the alley.)

GABRIELA: No way.
DOCTOR: Through the doors, past Ryan.
JAKE: We're not all going to fit in there.
GRAHAM: You'll be surprised. Ryan, this is Jake and Adam.
DOCTOR: Come on, Yaz.
YASMIN: No.
DOCTOR: Sorry?
YASMIN: There was a device in there. I couldn't get it free in time. It looked really important to them. I want to go back and get it.
DOCTOR: We don't have enough time.
YASMIN: You go. Come back for me in, what, I don't know, an hour or something.
DOCTOR: It's too dangerous.
YASMIN: We need to know why Adam was taken there and what they did to him, and how this is all connected to those other events.
GABRIELA: I'll come with you. I'm more than ready to fight something.
DOCTOR: One hour.
GABRIELA: Hey, I'm Gabriela. You must be Yaz.
YASMIN: Come on. It's through here.

[TARDIS]

(In flight.)

JAKE: So the box is the doorway to this building?
DOCTOR: No building. You're still in the box.
JAKE: But the box was smaller than this.
DOCTOR: The inside of the box is bigger than the outside.
JAKE: That's not possible.
DOCTOR: It clearly is, cos you're in it.
GRAHAM: It's a Space and Time ship, mate.
JAKE: Don't be stupid.
GRAHAM: Well, excuse me, Inspector Morse, but I ain't the fantasist round here.
DOCTOR: Adam, you really don't look well. I need to do an MOT.

(She jabs something into his neck.)

ADAM: Ow!
DOCTOR: I did say it'd hurt.
ADAM: No, you didn't.
DOCTOR: Well, I meant to. It takes a blood sample for analysis. So, International Space Station. Was it awesome?

(She uses a stethoscope.)

ADAM: Really awesome.
DOCTOR: Best bits?
ADAM: Just watching the planet turn across a day. The aurora borealis. Seeing hurricanes start to form from above. It just changes how you... see everything.

(A phone rings.)

DOCTOR: Incoming call.
SUKI [on screen]: Is this the Doctor?
DOCTOR: Aramu, Suki. Everything all right?
SUKI [on screen]: You said to call if anything else unusual happened.

[Madagascar]

(The TARDIS materialises on the beach.)

ARAMU: Suki? This is not an ordinary day.
SUKI: No. Very not ordinary.
DOCTOR: Before you show me unusual, can me and my friends make use of your lab?
SUKI: Where did you go?
DOCTOR: Busy day.

(Walking along.)

SUKI: Still can't believe what we saw earlier.
DOCTOR: He's not the first person to die like that today. Same thing happened to a young woman in Peru. They're linked. I need to work out how. Plus we've got a sick astronaut getting sicker by the moment.
GRAHAM: So you two know each other how?
ADAM: We're separated.
JAKE: We're married.
GRAHAM: Well, one of yous is in for a shock.
ADAM: One of us doesn't like putting the work in.
JAKE: I came halfway round the world.
ADAM: Seven months too late.
GRAHAM: Boys. Maybe now is not the moment. Let's get inside. Come on, son. You can do it. Few more steps.
DOCTOR: The birds are looking wrong here, too.
ARAMU: I only saw it the past few days. At first I thought it was okay, you know? It's not the first bird to fly off its course.
RYAN: It's not native to Madagascar?
ARAMU: No.
RYAN: Hey, don't get too close.
ARAMU: That's not the only one. Others have started to come.

(A huge flock.)

DOCTOR: Yes, they have. But why here?
RYAN: There was a dead bird in that deserted hospital, and all over the dumping ground where Gabriela and Jamila were camping.
DOCTOR: And now they're circling this beach where Zach washed up.
RYAN: Alien birds?
DOCTOR: I don't know. If I could get hold of one to analyse it.
RYAN: Good job I've got one in my backpack. Picked it up when I were in Peru.
DOCTOR: That's why you smell of dead bird. I thought you'd changed your shower gel.
GRAHAM: Doc! Doc, Adam's in a bad way in there. I think we made a mistake by disconnecting him from all that gubbins in Hong Kong. Or maybe you just want to stand out here watching birds.
DOCTOR: More like they're watching us.
ARAMU: You go inside. I'll keep my eye on them.
DOCTOR: Let's take a look at Adam. Let us know if anything changes, Aramu.

[Warehouse]

GABRIELA: So, I guess you recognise me.
YASMIN: No.
GABRIELA: Two Girls Roaming.
YASMIN: I haven't seen it.
GABRIELA: What's the matter with you people?

(One of the gas-masked people isn't dead.)

YASMIN: In here.

(Yasmin picks up the panel.)

GABRIELA: Is that what we came for?
YASMIN: Yeah.
GABRIELA: Okay, so let's get out of here.
YASMIN: It's connected into the systems. I want to see what I can find. It looks like this lab is part of a triangulation of signals with two other locations. One's Madagascar.
GABRIELA: Hide.

(They do.)

YASMIN: That's one of the creatures Jake shot. What's it doing?

(It puts its hand on a triangular control and vanishes.)

GABRIELA: Whoa! Where did it go? What did it just do?
YASMIN: It's a teleport station. We could follow it.
GABRIELA: Are you crazy?

[Laboratory]

RYAN: So here's your present from Peru.
DOCTOR: Ryan, will you dissect it for me?
RYAN: What?
DOCTOR: You must have done it at school. Doesn't need to be elegant.
RYAN: Good. Cos it won't be.
DOCTOR: Nice lab. Very well equipped.
SUKI: Thanks.
DOCTOR: Right. First things first. How are you off for broad-spectrum antibiotics?
SUKI: Yes, but only a small...
DOCTOR: Great!
SUKI: ..supply.
DOCTOR: Graham? Jake. See if you can rig up an IV. We need to get some medicine into Adam. Try and stabilise him.
JAKE: I have no idea how to do that.
GRAHAM: I'll give you a hand. I've seen a few intravenous drips in my time. Finally, it comes in handy.
DOCTOR: I might need a high-powered microscope, blood cultures, rapid genome sequencing, a spectrophotometer, and a super fast incubator.
SUKI: I've got most of that.
DOCTOR: Suki Chang, on a Madagascan beach, excellently equipped and ready for anything. Ooo, can I use your computer? Right. I want to see what's going on inside Adam. Gonna use your laptop to download the readings I took from him earlier. So what is it you do here?
SUKI: We're working on a marine filtration system connected into the Crystal Oceans Initiative.
DOCTOR: Ah. Hence the water filtration system. Micro version, is it?
SUKI: You take a lot in, very fast.
DOCTOR: Yes, I do. It's one of my skills. Ah. Here we go. Initial blood analysis for Adam.
GRAHAM: You okay, Doc?
DOCTOR: I'm sorry, Adam. Your bloodstream's been infected with an alien pathogen, presumably in Hong Kong.
JAKE: Is it bad if I don't know what a pathogen is?
GRAHAM: I'm glad you asked that, cos I... I didn't want to look stupid.
DOCTOR: It's a microorganism that carries disease. Alien bacteria, which is latching on to lifeforms and killing them. I'm afraid it's inside you, Adam, and right now, I don't know how we stop it overwhelming you.

[Warehouse]

GABRIELA: You really want to follow that creature. We're seriously going to do this?
YASMIN: Yeah.
GABRIELA: Without knowing where we're going?
YASMIN: Yeah.
GABRIELA: What's the worst place we could end up?
YASMIN: Long list. You don't want to know.
GABRIELA: You are crazy!
YASMIN: Two Girls Roaming. Ready?

[Madagascar]

(By the beach, watching the sun set.)

GRAHAM: I know you're worried about your husband, mate, but he's in good hands with the Doc.
JAKE: Just go away.
GRAHAM: What did he mean when he said, seven months too late?
JAKE: I was supposed to come out and see him launch. Say goodbye as he went off to the ISS.
GRAHAM: And you didn't go.
JAKE: He knew what he was taking on with me. I don't do emotions. And I'm really not good at sticking with things, you know? Commitment. Also, I really don't like foreign travel.
GRAHAM: Wow. So you were quite the catch, then.
JAKE: Yeah, he's a lucky, lucky bloke. My husband is an astronaut. Do you have any idea how hard it is being married to somebody that impressive? It sort of sends me the other way. I wallow in being unreliable. Like I'm punishing him.
GRAHAM: What for?
JAKE: Not being honest.
GRAHAM: No, sorry, you lost me.
JAKE: If he's that impressive, if he's that amazing, which he is, he can't love me the way he says he does. It doesn't make sense. Why would he?
GRAHAM: Oh mate, I don't think he's the one you're punishing.

[Tunnel]

GABRIELA: We're still alive. We didn't die!
YASMIN: Didn't teleport into an active volcano. Result!
GABRIELA: What do you think this is?
YASMIN: Some sort of alien colony. Look at all this stuff. What even is it?
GABRIELA: If we're on an alien planet, then what is that?

(Large metal tube, with number 537 painted on it.)

YASMIN: That... is part of a submarine.

[Laboratory]

SUKI: I've gene-sequenced blood cultures from Adam and that bird.
DOCTOR: Wow, you are fast.
SUKI: If I track changes in the optical density and confirm the bacteria's growth rate, we might be able to use that data to genetically engineer a virus.
DOCTOR: That's what I was thinking. We're so sympa.

(Jake walks in.)

ADAM: Hey.

(The growth is spreading onto his face.)

JAKE: The antibiotics aren't working. He's getting worse.
GRAHAM [OC]: Doctor! (runs in) Doc. Doc. Aramu says that the birds are getting really angry out there.
RYAN: Not surprised, if this is what their insides are like. Take a look. They're full of plastic.
SUKI: Once plastic gets in the ocean, birds mistake it for food. I've seen hatchlings regurgitate 200 individual pieces.
DOCTOR: It's feasting on the plastic in the birds and taking them over. The alien pathogens attacked the plastic. The plastic metastasised as if it was living. Oh. Autons? No, it can't be Autons. They don't work like this. Not bacterial. Come on, brains! Move it along!
GRAHAM: Did she say brains, plural?
RYAN: How does that explain what happened to Jamila? Like, she just got taken over.
DOCTOR: Yeah, how does it? It attacks the plastic in the birds, but there's no plastic in humans. Except... Oh! Microfiltration.
GRAHAM: Hey, Doc. That's not a thought, that's just a random phrase.
DOCTOR: No, no, no. That's a very big thought. The microfiltration system in the water. It filters out...
DOCTOR + SUKI: Microplastics.
DOCTOR: Alien bacteria homing in on microplastics because humans are full of them.
GRAHAM: Excuse me, I'm not full of plastic.
RYAN: Full of something.
DOCTOR: I'm afraid you are, Graham. It's in the air, it's in your food, it's in your water. Humans have flooded this planet with plastics that can't be fully broken down, so much so that you're ingesting microparticles whether you know it or not. You're poisoning yourselves as well as your planet. An alien bacteria has come to this planet, and it found a feast.

(Aramu tries to run, stumbles, and the birds smother him.)

GRAHAM: Hey, Doc, let's get rid of this bird, cos it really, really smells.
DOCTOR: No. Look.
GRAHAM: What?
DOCTOR: See what the birds' natural enzymes are doing.
GRAHAM: Oh, yeah. Clear as mud.
DOCTOR: Planet Earth. So clever. Two strains from Peru fighting back, ganging up on the bacteria, holding it back to allow natural decomposition.
RYAN: Come on. Catch me up on this, please.
DOCTOR: Ryan Sinclair picks up a dead bird in Peru, and might just have saved the world.
RYAN: Well, I am here for you guys, you know?
SUKI: If we isolate and boost the enzyme, then splice them, we'd have one supercharged virus.
DOCTOR: Yes, we would. (commdot) Yaz, how are you doing? Cos we've literally got the most exciting rotting bird that I've ever seen.

[Tunnel]

YASMIN: I don't want you to panic, but we followed one of those things through a teleport, and now I think we're on an alien planet.

[Laboratory]

DOCTOR: Well, you don't do things by halves.

[Tunnel]

YASMIN: Also, I think we found the missing submarine.

[Laboratory]

YASMIN [OC]: Not sure how that got here. Oh, and another thing.

[Tunnel]

YASMIN: The lab in Hong Kong was sending data to two locations. One in the middle of the Indian Ocean, but the other is in Madagascar, where you are right now.

[Laboratory]

YASMIN [OC]: Doctor. Doctor, did you hear what I said?
DOCTOR: Yeah. Thanks, Yaz. Sit tight. Suki Cheng, out here all alone in an over-equipped lab. I should have spotted it straight away.
RYAN: What's happening? Where's Yaz?
SUKI: I was so worried when you turned up. When you took him from Hong Kong. But you've really helped. Got even more answers from you than we did from experimenting on Adam. We call the infection Praxeus. Trust me, it's smart, it's relentless, and it knows you're onto it.

(She teleports away.)

DOCTOR: Oh, I'm a sucker for a scientist.
JAKE: Where did she just go?

(The birds outside are getting noisy.)

DOCTOR: We need to get out of here.

(Then it goes quiet.)

JAKE: Have they gone?

(Birds crash through the skylight.)

GRAHAM: Doc, come on!
DOCTOR: Take cover! Let's go!
GRAHAM: Come on!
DOCTOR: We need to get out. Don't let them scratch you, they'll infect you. I need to get the samples.
GRAHAM: Doctor, come on!

(Jake is helping Adam.)

JAKE: This is why I don't go abroad!
GRAHAM: Let's go! Doc, catch!

(He throws her an oar to wave at the birds.)

GRAHAM: Come on!

(The Doctor shuts the lab door behind her.)

[Madagascar]

DOCTOR: Head straight for the TARDIS, quick as you can.
RYAN: They've seen us! They're following!
DOCTOR: Just keep running! In here, all of you. Come on, Ryan!

(TARDIS door is closed just as the flock get there.)

[TARDIS]

DOCTOR: Yaz, we're on our way, locked in on your commdot signal. We're coming for you, wherever you are. If Praxeus is being spread by birds, it could get around the world incredibly fast, attacking and infecting every living thing. We may potentially have a cure, but we don't know if it works.
ADAM: Test it on me.
DOCTOR: No. Too dangerous.
ADAM: It's too dangerous if we don't do it. You said yourself there's no time. You need a clinical trial, a human body, and now you've got one.
JAKE: No.
ADAM: We don't have time to argue.
JAKE: Adam, no. No way. I'm not gonna let you.
ADAM: It's not your choice to make.

[Tunnel]

GABRIELA: Yaz, look.

(One of the rubber suit beings.)

YASMIN: Looks like it was trying to get somewhere but its injuries were too bad. I wanna know what they are.

(She easily removes the gas mask to reveal just a humanoid nose sticking out of the plastic infection.)

GABRIELA: Oh, my God!

[TARDIS]

DOCTOR: Bioreadings synced with the TARDIS. If the antidote works on you, the TARDIS will make more. Sure?
ADAM: Stop faffing about.

(She injects his hand. It hurts.)

(The TARDIS materialises.)

DOCTOR: We've landed. But where? Stay in here. We'll be as quick as we can. With me.

(Ryan and Graham leave with the Doctor.)

ADAM: God, you look miserable right now.

[Tunnel]

DOCTOR: Yaz! Found you.
YASMIN: Thanks for coming to get us, eventually.
DOCTOR: Look at you, going off on your own and not getting killed.
YASMIN: Plus, totally found an alien colony.
DOCTOR: Sort of. It is an alien construct, but it's not an alien colony.
RYAN: Then where are we?
DOCTOR: A long way below the Indian Ocean, beneath a gyre of plastic pollution.
GRAHAM: We're under the sea?
DOCTOR: It's a naturally occurring hot spot where ocean currents trap pollution. There are five major gyres on Earth right now. Praxeus is attracted to plastic. It's built a whole environment here from the plastic. A world of pure Praxeus! This is where it all started. Seabirds infected with Praxeus transporting the bacteria around the world, transferring it to humans when they attack.
RYAN: But how does the alien bacteria end up in the Indian Ocean in the first place?

(She does another scan.)

DOCTOR: There's something else down here, and I think it's connected to our friend Suki. Come on.
RYAN: What are you looking like that for?
YASMIN: Thought I'd discovered an alien planet on my own.
GABRIELA: We're at the bottom of the Indian Ocean.

[TARDIS]

JAKE: How are you feeling?
ADAM: Dying.
JAKE: Not allowed.
ADAM: Dying man's wish. (they hold hands) Stop dodging life. Please.

[Tunnel]

YASMIN: We followed it through the teleport and found it here.
DOCTOR: Humanoid. But not human. Infected with Praxeus, but the body hasn't disintegrated. Must be due to the different biology.
RYAN: I don't get it. Why were these guys experimenting on Adam?
DOCTOR: Maybe for the same reasons we are. To find a cure.

[TARDIS]

(Adam groans and creaks.)

JAKE: What does all this stuff mean?

(A pedestal rises up from the floor and an alarm sounds. Adam's lifesigns start flashing red.)

[Tunnel]

(Suki comes in through an airlock.)

DOCTOR: Going somewhere? Who were they, Suki, the infected people in the hazmat suits?
SUKI: My crew. I'm the last one left.
GABRIELA: Wait. That's a spaceship, right?
DOCTOR: Well, the back end of one, yes.
GABRIELA: Just when I thought things couldn't get any madder. Whoa.

(Suki has a gun.)

SUKI: How did you get here?
DOCTOR: I was going to ask you the same question, but I presume that ship is how. So the question is, why?
SUKI: Praxeus devastated my planet. The survivors were assigned to lab ships to find an antidote for the few of us left alive.
DOCTOR: You're infected too.
SUKI: Cellular mutation is slower for us.
DOCTOR: If you're scientists in lab ships, please tell me you didn't bring this infection here deliberately.
SUKI: Praxeus breeds in plastic, and this planet is saturated in it. We travelled across three galaxies to find the perfect living laboratory.
DOCTOR: To use Earth as a petri dish, destroying one race to save the remnants of your own. But this down here, this environment, it wasn't deliberate.
SUKI: We lost control of the shuttle on entry. Crash-landed. Bacteria flooded out, irradiated, formed this world.
DOCTOR: And a broken spacecraft sending out pulses of energy from the bottom of the ocean was enough to down and frazzle a returning space capsule. This is the centre of where everything's been happening! Your arm. You've been scratched by those birds. You've had a double dose of Praxeus.
SUKI: But you've showed me how to find a cure. Thanks to you, my mission was successful. They already have the transmission of how the cure could work.
DOCTOR: No> Suki, the cure is designed for humans, and we don't even know if it works on them. If you're not human, who knows what will happen? Please tell me you haven't administered it on yourself.
SUKI: Stay out of my way.
DOCTOR: Stay here.

[Shuttle]

DOCTOR: Suki, listen to me. We can work together on this.
SUKI: Get out of here.
DOCTOR: I wouldn't use that in here. Not with those reverse pulse proton engines. Very unreliable. No wonder you crashed.

(Scans with the sonic.)

SUKI: Put that thing down.
DOCTOR: Sortable, though. Organic fuel cells. Oh, hang on. I'm having half a thought. Ooo, this one tickles. What is it? Oh! Yes! You can store anything in organic fuel cells. Anything vaguely organic. Look at us, Suki. Two brilliant scientists. We can fix this. Work together, find a cure for you, and then we can stop Earth from being taken over by Praxeus.

(The infection is appearing on Suki's arm.)

SUKI: What's happening to me? It's spreading. How do I stop it? Help me!

(But she is covered and explodes into dry dust very rapidly.)

[Tunnel]

RYAN: You okay? Where's Suki?
DOCTOR: Succumbed to Praxeus. But I think this may give us a way through. I need a crew in here.

(Adam and Jake come out of the TARDIS. No Praxeus scales on Adam's face any more.)

JAKE: Count us in.
ADAM: Hi. Turns out it worked.
JAKE: Your machine spat this out.
DOCTOR: That's the antidote.
JAKE: Oh, and by the way, where the hell are we?
DOCTOR: Follow me. Lots to do.

[Shuttle]

YASMIN: Engine vents on, apparently.
RYAN: System set to automated timed venting. I think.
GABRIELA: Manual bypass, bypassed.
GRAHAM: Dials on full clockwise.
DOCTOR: I said anticlockwise!
GRAHAM: Just testing.
ADAM: Organic fuel cells loaded with Praxeus antidote.
JAKE: Trajectory aligned. Comms off. Spatial regulators disabled.
DOCTOR: Organic fuel cells filled with Praxeus-killing virus, as tested on Adam, check. Autopilot system set for the Earth's stratosphere, check. All systems set for automation.
JAKE: No idea what any of this means, but is that literally the controls for up, down, left and right?
DOCTOR: Yeah.
JAKE: Adam Lang, your job is so easy.
COMPUTER: Shuttle initiating autopilot take-off.
DOCTOR: Gold stars for my apprentice engineers.
GABRIELA: What is actually happening?
DOCTOR: Once the ship is in the stratosphere, the engines discharge the virus in one superpowered burst, dispersing it around the world, killing Praxeus stone dead. Hopefully. Only one tiny flaw in the plan. Send this into the atmosphere, it'll rip a hole in this world, and we'll be crushed under the entire Indian Ocean.
GRAHAM: That's more than a tiny flaw, Doc.
DOCTOR: And that's why I set the autopilot. So everybody, out, now.

[Tunnel]

(Sonicking the airlock.)

DOCTOR: Go.

(Bang! Fizzle.)

GRAHAM: What was that?
DOCTOR: Autopilot failure. It can't connect.
RYAN: It's gonna work, though, right?
DOCTOR: I dunno. It might not. But it's definitely going to take off. We need to get out of here.
JAKE: What if it doesn't work?
DOCTOR: Too late to fix. Come on.

[TARDIS]

DOCTOR: Got to be fast taking off.

(A big explosion comes down the tunnel.)

ADAM: Where's Jake?

(The shuttle is taking off.)

ADAM: Where's Jake?
YASMIN: He was right behind us.
JAKE [on screen]: Are these comms on? Spacecraft to blue box, can you hear me?
DOCTOR: Jake, what are you doing?

[Shuttle]

JAKE: Manual pilot making up for broken autopilot. Any idiot can fly a spaceship, right?

[TARDIS]

ADAM: Jake. I don't want this.

[Shuttle]

JAKE: Maybe I do.

[TARDIS]

JAKE [OC]: Maybe I need this.
DOCTOR: You're entering into the stratosphere.
JAKE [on screen]: Yeah, that really doesn't mean anything to me.

(Things going bang behind him.)

JAKE [on screen]: But if I was a betting man, and my husband would tell you I really am, I'd say the automatic release is bust. Tell me what I need to do.
DOCTOR: The controls by your right hand will vent the antidote. You need to flick the three switches at once.

[Shuttle]

JAKE: I'm going to give it a go.

[TARDIS]

ADAM: The ship's gonna break up.

[Shuttle]

DOCTOR [OC]: Jake, you have to wait until the shuttle's in the right position.
JAKE: Adam? Adam, I'm sorry I wasn't at the launch. This is me not dodging. Don't say I never listened to you.
DOCTOR [OC]: Shuttle's in position, Jake.
JAKE: Dispersing antidote... I think.
DOCTOR: Jake, you've done it. Antidote particles being dispersed into the jet streams.

[TARDIS]

JAKE [on screen]: Hope it works. The ship's very knackered. About to blow!
GABRIELA: You can save him, right?
DOCTOR: No.

(They lose Jake's signal.)

GRAHAM: Doc, come on!

(Explosions on the shuttle. The Doctor works the TARDIS controls, and Jake is there with them.)

ADAM: I hate you.

(Adam and Jake kiss.)

DOCTOR: Yes, I can save him, just, if I materialise around him in the millisecond before the ship breaks up.
GRAHAM: Nice work, Doc.
DOCTOR: What can I say? I'm a romantic.

[Madagascar]

DOCTOR: I guess this is goodbye, then.
YASMIN: Keep the planet safe for us.
GRAHAM: Cos we'll be coming back, so it better be in good nick.
RYAN: Or we'll know who to blame.
ADAM: Thank you.
DOCTOR: Our pleasure. Really.
JAKE: Although I have to say, worst thing about saving the human race? Nobody knows it was me. Least I could get was a statue.
GRAHAM: So what's the plan now for you two?
ADAM: Dunno. Spend some time together. We never had a honeymoon because he didn't want to go abroad.
JAKE: Maybe now's the time.
GABRIELA: I'll come with you.
JAKE: How's that a honeymoon if you're with us?
GABRIELA: We can vlog about it.
GRAHAM: What you gonna call it, Three Idiots Roaming?
YASMIN: I like it. It's snappy.
RYAN: And factual.
JAKE: Yeah, you guys can go now. We'll take the planet from here.
GABRIELA: Hey! Come find us some time.
DOCTOR [OC]: Planet Earth. Seven billion lives. Separate, and connected, from the edge of the atmosphere to the depths of the ocean.

Transcript originally provided by Chrissie. Adapted by TARDIS.guide. The transcripts are for educational and entertainment purposes only. All other copyrights property of their respective holders.