It won't be funny if we end up in a Romanian jail.
Relax. Nobody's been up here in years.
Oh, Christ.
This way?
It's up there? Hey. You sure it's up there?
Yeah. He's sure, Mr. Mick.
Well, he better be right. You tell him.
Come on. Let's get the stuff.
O ye of little faith.
Should be a gold mine.
Why the hell would they build a church out here?
Check this.
Here we go.
My God. Look at the walls.
There's nothing here.
So where's the cave?
You're standing on it.
So how do we get in?
Fire in the hole.
Perfect. Let's go.
Shut up.
Shut up!
What the hell is that?
You know what? It's more than a cave.
This one could run deeper than Postojna.
Look at this.
If this is what I think it is, it's going to be a fantastic find.
Let's have a look at it, shall we?
- Ready? - Yeah.
Hear that? Running water. That's a good sign.
Nic?
Come. Have a look at this.
We're going to need cave divers.
I know just who to call.
But no Ansel Adams, Briggs. Hugh Hefner.
No picture, Charlie.
- This antenna's a piece of junk. - How's that?
Got it.
Strodey.
Get your skinny ass down here.
Boys. You found it yet?
No. We looked exactly where your sonic mapping said we should.
Christ. My kids could get in and find it quicker than you two.
- Ready,Top? - Yeah.
- Jack and Tyler back yet? - Not yet.
That's Tyler's unit. He found it.
Bastard did it again.
Jack's gonna be pissed. He called time five minutes ago.
You don't have to say anything. I know it was stupid, but we got it.
I call time and you surface.
Okay.
How's that? You got a signal there yet?
Not yet, Strodey.
- And now? - Yeah. Yeah.
- Dr. Nicolai. - Hello.
Hey. It's Jack.
You got some good news?
Yeah. I've got the funding.
You do? Really?
We've done the surface scans. The cave is huge, Jack.
There is a river off the main cavern...
...and there's nowhere it can come out for at least 90 miles.
Sounds like the Amazon of underground rivers, huh?
- Yeah, it does. - Dr. Jennings, our biologist...
...is bringing a cameraman to shoot the whole thing.
But, you know, it's gonna be tough.
Which is why I need your team, and I need you to run the show.
Great. When do we start?
We want to start right away.
We're in 100 percent. You got it.
That's great, Jack. I can't wait to see you here. Ciao.
- Thanks, Dr. Nicolai. - Bye.
Get out of here. Come on.
- Here, I got it. Excuse me. - Here you go.
Come on. Let's go.
- Good to finally meet you, Dr. Nicolai. - Pleasure.
- Let me show you around. - Please.
- What do we got? - That's the main cave...
...hidden under a church. And half the mountainside.
- Tyler. - Yeah?
Everything made it okay.
Take a look at this mix computer. It got a little banged up.
Yep. All right. Break it down and reinstall the programming.
Hello.
I'm just gonna go visit with a fellow scientist.
- Hi. - Hi.
I'm Tyler McAlister. I'm the first scout.
One second.
- Do you mind if I--? - Sorry.
Let me just move this for you.
Okay?
- Dr. Jennings. - It's good to meet you.
This is Alex Kim, our cameraman.
- Yeah. I've seen your work. - Heard a lot about you too.
- Good to meet you. - Thanks.
So it's unusual for a rebreather. Who modified it?
That would be my brother, Jack.
- Really? - Yep.
I did all the reprogramming, though.
And why the canister?
We're using lithium hydroxide to filter out the CO2.
It's a little dangerous, but it's much more effective than calcium.
Hope you got a redundancy for this meg.
There's actually a triple redundancy. It's the backup, a primary and a HUD.
So you can stay submerged for what, 18, 20 hours?
Twenty-four.
Kate. Alex.
This is Jack McAlister.
- Dr. Jennings. - It's a pleasure.
We read about some of your Yucatán expeditions.
- Pretty amazing. - Thank you. Thank you.
And I understand you have a great interest in cave biology, Mr. McAlister.
I'm starting to.
- And it's just Jack, please. - Kathryn.
Perhaps you wanna see some samples?
Yeah, yeah. Sure. Please.
Hey, bro.
Double-check all the rebreathers.
Yeah. One in 14.
One in 14?
It's the number of cave divers that die each year.
What's this?
It's all that's left of some poor guy they found in the mouth of the cave.
Tyler. Let's go.
So how did you hook up with these guys?
My dad had a dive business in north Florida...
...and when Jack got out of high school...
...he kind of took him under his wing.
We're all kind of like family.
And Tyler?
He joined the business out of college.
Briggs we found table-dancing in a club outside Calgary.
The Romanian boys don't use the heads-up display.
- We put him on the team. - Everybody, listen up.
Here we go.
- You all right, Strode? - Yeah. I got it.
I've been analyzing these readouts...
...and here's what we got.
There's an enormous cavern about 300 feet down...
...just below the cave entrance.
Dr. Nicolai's already named it Titan Hall.
Oh, yeah. It's huge. Believe me.
There's a sump-- Strode?
--right about here...
...which then leads to this underwater passageway.
Look who's here.
We need to find a dry cavern somewhere in the system...
...where we can set up advance base camp, and Dr. Nicolai and Kathryn...
...can gather their samples.
Now, we'll be under for 12 days.
We're gonna go deep on this one.
- Yeah. - All right.
Top? Anything you wanna add?
Yeah. Everybody remember...
...this cave is a very serious piece of work.
It's already taken at least one life.
Respect the cave.
Briggs, you're gonna take first scout.
- Right on. - Any questions?
All right, listen. A toast.
- To virgin caves. - To virgins everywhere.
- To caves. - Cheers. Thank you very much.
Virgin everything.
They built the church to seal the cave as a display of God's protective power.
Now, try to imagine...
...these Knights Templar entering the cave...
...and according to the local legend, fighting these winged demons.
- Demons, huh? - Yeah.
Well, did they win?
Unfortunately, no.
European legends always have sad endings.
There you go.
Oh, yeah.
- The ladder is quite safe. - Yeah. I hate ladders.
Next thing you know, they're putting in elevators.
She's such a showoff.
It's the only way to go, doc.
Oh, man.
Titan Hall.
It's awesome.
Pre-dive checklist. O2 sensors calibrated?
Calibrated, check.
- Oxygen running at 0.4? - 0.4. Check.
Now, you find it, you name it.
- Make it good. - First scout's privilege, Top.
I got ideas. You know I'll come up with something.
Okay. Synchronize watches to 0811 on my mark.
Three, two, one...
- ...mark. - All okay?
I don't think it could be any better, Ty.
- Yeah, I bet. - All right. Here we go.
This is a long passage, so I want you to pace yourself.
Yeah.
Turnaround's one-third, okay?
I find a dry cavern, I'll give you a call, Jack.
- You do that, would you? - Go and get it.
How's it looking down there, partner?
It's dark, it's deep and it's wet, Jack.
Give us your current depth.
Depth at 162.
And what's your gas reading?
O2's reading 1800.
- How you feeling, Briggs? - I'm feeling pretty good, Top.
- How you feeling up there? - I'm all right. I'm all right.
How about the warning lights? How they look?
Nothing yet.
There's a curve in the tunnel up ahead, though.
Probably gonna lose you on the dark side of the moon.
Tell Tyler I'll call him from first base camp...
...after I set up that fiber optic.
You know, I'd warn you not to be so arrogant...
...but then you'd have no personality at all.
Come on. Take away the arrogance, there's nothing left.
- There he goes. - That's it.
Thanks, Strode.
We need you ready around 0100 hours, all right?
Oh, I've been ready.
You got something to say, say it.
- You know I'm the best scout. - Maybe so...
...but I can count on Briggs.
First scout consolation prize.
- Yeah. - You wish it was you in there?
Yeah. I just wanna be first in a place nobody's ever been.
Well, you and I aren't that different.
I mean, if I find something unique, I wanna put my name on it.
So, what happened?
- It's my brother's call. - Hey, Ty.
I checked the line three times. There's nothing wrong.
System's fine, we just don't have a signal yet.
Keep checking every five minutes till we get something.
What's up?
If Briggs doesn't show in 10, I'm sending you.
Come on. It's Briggs. He's probably showing off.
Listen, you're probably right, but go get ready anyways, okay?
Jack. Guys. I got him.
- Wakey-wakey, Titan Hall. - Oh, Jesus.
Is anybody there? All right. Get up.
Morning, Briggs. We're all here, buddy.
- Where are you? - Good morning to you too, Top.
I'd say I'm sitting at advance base camp.
Which will now be forever known as Kublai Khan.
About how far in would you say, Briggs?
Only about 2.4 miles, Jack.
- Fantastic, fantastic. - Two-point-four.
I'm uploading the data now. Read it and weep.
It's amazing in here, man.
I haven't seen a hole like this in a long time.
- Shit. - Briggs.
Yeah, yeah, yeah. Hold on a sec. Something just ran past me.
Got it.
Kathryn, can you and Nicolai see this?
It's some kind of a large rat or a mole or something.
Buckteeth, webbed feet. Looks a lot like Tyler.
- No-- - You all right, man?
Shit.
Yeah. What the fu--?
I think I pissed him off with that Tyler comment.
Hey, listen, man. Good work. Get some sleep, all right?
Yeah. Yeah. Some sleep.
- You need anything down there, man? - Hold on a sec.
Briggs?
Yeah.
Yeah. Hold on, guys. There's-- I'm gonna try to get--
There's something that--
- Briggs. - What's up, Strode?
- Could be feedback. - What the hell was that?
- Goddamn it. - Briggs, key me if you can hear me.
Fiber optic must have snapped,huh?
Maybe we should send in a second scout just to be safe.
No. Come on. We gotta get in the water.
Top and I are in the water in 30 minutes.
Strode, Tyler. Fix the cable on the way in. Let's do it.
All right. Let's take it a little slow.
Break in the line could be anywhere.
Right on your tail, mate.
It's not bad, huh, Top?
Yeah. There's a lot of life in here.
You okay?
Yeah. Just thinking about Briggs.
He can take care of himself.
- How long till we reach the cavern? - It's a long run, Nicolai.
Enjoy the ride.
This beats anything in the Yucatán by a mile.
Hey, Kim. Did you get a shot of those cave draperies?
Sick, dude.
I got it.
It's totally rocking.
Dr. Nicolai, you and Kathryn should check this out.
Advance base camp should be about 200 yards ahead.
Yes, Jack. Thank you. We'll see you there.
Yo, Briggs?
Briggs?
Hey,Briggs?
About time you two ladies got here.
Come take a look at this.
We're not the first ones here after all.
Looks like somebody lost his boots.
What the hell was that?
Tyler, hang on.
Gonna make a jump here for a second.
Hey, Strode. How are you doing?
Hey, good. I think I saw one of those moles. Be right back.
All right. I'll keep looking for the break.
Strode, I found the break right here.
It's gonna take me a few minutes.
Strode? Hey, Strode?
Yeah. Right here. Just give me another minute.
There's a flat area just up there where we can set up camp.
- Any hot showers? - Oh, baby. That would make my day.
I've had enough water for one day.
Tyler? You still reading me, mate?
Tyler?
What the hell?
Son of a bitch.
Hey, Tyler.
Tyler, you read me?
What the hell? Strode, this cable looks chewed.
Mate, you there?
- Help. Help. -Strode?
- Strode? - Help!
Strode? Strode, can you hear me?
Where are you, Strode?
- Tyler! - Jesus.
- Strode! - What was that?
Get her, Top.
- What's happening? - Take it easy.
Tyler. Tyler, wait.
- You all right? - Yeah. Yeah. I think so.
Where's Strode? Huh?
I don't-- I don't know.
- Top. - Bring the J-bar.
He said "help," like he was being attacked.
So I went back for him, but I don't know what the hell exploded.
At least the dive line's intact.
Let's keep our eyes open.
Looks like the whole damn tunnel collapsed.
He's gotta be in here somewhere. This is the only way through.
Son of a bitch.
- Jack, it's-- - That's his counterlung.
Oh, man. This isn't good.
Jack, look out. It's coming down.
Oh, shit.
Jack, back on the dive line.
All right. Listen up.
We have a few realities to face here, people.
The first is that we're not going out the way we came.
The passage is completely blocked.
The second...
...is that we're not even gonna be missed for 12 days.
Which is right about when our supplies run out.
- We have to find our own way out. - Hold on a second, Jack.
You still haven't told us what happened to Strode.
Tyler said it sounded like he was being attacked.
He was Special Forces, for chrissake, Jack.
He knew what the hell he was doing.
Now, something got him down there.
And I'll bet it's the same damn thing that got whoever owns those boots.
We're all hurting, man.
Strode was a friend to all of us.
Don't you forget that.
What do you think, Dr. Nicolai?
Is there anything that could've attacked Strode?
I don't know.
The mole is the largest animal we've seen in this type of system.
Our friend here does prove there's an abundant food supply.
Question is, is he at the top of the food chain, or is there something else?
Look, Strode could've just screwed up his mix.
Narcosis, hallucinations. It happens.
I mean, he panics, he ruptures his scooter.
Whatever it was, it doesn't matter now.
Right now, our primary concern is getting out of here alive.
Jack, this is the Carpathians.
We can spend an eternity trying to find a way out...
...if there even is one.
Come on, Jack. We wait.
- A rescue team will come for us. - Dr. Nicolai.
We're a mile below the surface.
And three miles in.
The best people to get us out are all right here.
We are the rescue team.
Here's how it's gonna go:
Top and I, we're gonna start scouting for an exit immediately.
Now, I'd recommend that you all get some rest. You're gonna need it.
Top.
We never lost anybody, Top.
I don't like it, Mac.
Something's not right.
No shit, buddy.
Narcosis, my ass. That's bullshit and you know it.
I'm not getting into this.
Why is that, Tyler?
Because you forgot to stick with your dive buddy?
You asshole! I had no idea--
Stop. Hey! You eyes!
Hey! Stop it!
You guys, cut it out! Stop it!
Hey! We just lost a friend and this is how you deal with it?
Come on.
Never seen a white algae bed before.
Yeah. Looks like we found the base of the food chain.
It's not the base I'm worried about.
Someone made it this far.
Let's keep moving.
Nicolai, look at this.
It's a parasite.
- That's from the mole. - Yeah.
And this is from the salamander.
It's the same parasite.
We should have tried door number two.
It looks like it opens up.
I'm gonna try to slip through.
Oh, shit. Hey, Top?
Yeah?
You mind backing up, bud?
Backing out.
Jack.
Jack! Jack!
Jack!
Get the medical kit!
- I got it, Top! Set him down. - What happened?
Oh, shit! Look at me. You all right?
- Top, what do you need? Tell me. - Jesus, Tyler!
- What happened, Top? - Found that hooked in his sling.
- What the hell is that? - I cut it off.
- Did you get a look at it? - No.
- It jumped me too fast. - Here, hold still.
- Jesus, how big was it? - It's big.
- How's it looking, bud? - Ripped you up pretty good.
You need an antibiotic. Give me a syringe.
Oh, you son of a bitch.
All right.
There's a resemblance to amphibian tissue...
...but these hair follicles would seem to rule that out.
The only thing I do know: this is definitely a predator.
Great. So now we're part of the food chain.
We always have been. We've just forgotten that, living in cities.
Just reflexes. Don't worry.
So, what is it?
Well, without DNA testing, it's impossible to tell.
This may be something we've never seen before.
Every cave organism we've discovered so far originated on the surface.
Over time, they've adapted.
Lost pigmentation and sight...
...developed a heightened sense of hearing and smell.
If this is a totally self-contained ecosystem--
Yes, we may have discovered...
...the primeval creature that has evolved in total isolation.
Well, it looks like a piece from those things on the mosaic.
- Look. - What?
There.
It's still alive?
- Those tendrils look familiar? - Yeah. The parasite.
Appears to be ubiquitous.
All right, let's pack it up.
It's time to go.
We should wait here.
Wow, that's just brilliant, doc.
You really want to be sitting here on your ass when the lights go out.
Okay, people, take only what you need, but keep your dive gear.
Hey, maybe there's a way to climb out.
Yeah, better up than down.
Looks like we found the owner of those boots.
Teeth marks.
Let's go.
Take a break right here.
Talk about a fork in the road, huh?
A fork or a dead end?
Where's Jack?
Scouting the tunnel.
So why aren't we helping him?
You know the drill, Briggs.
Give him a chance to read the sediment.
Yeah, I know the drill, Top.
You don't have to tell me about drills. Sonar gun's right here.
Relax.
What the hell's going on?
Come on, Jack. I just wanna get the hell out of here.
Well, maybe you ought to follow me, Briggs.
This is bullshit.
Jack didn't pick the dominant artery.
- Are you sure? - Yeah. I'm sure.
This is the one right here. Take a look at it.
There's something in there that wasn't there before.
Well, why don't you go scout it out for us, Briggs.
Forget about it.
On belay.
You're safe to climb.
You gonna let me change that bandage when we get to the top?
I'm all right.
Looks like it's getting infected. You sure?
How many expeditions we been on together, Top?
Too many.
- We need a break. - Not with that thing out there.
You gotta let them rest, Jack.
- Once we hit the water. - Water?
- I don't hear any water, Jack. - Yeah.
I smell it.
- Not now. - We're gonna need footage like this.
Get that camera out of my face!
- Hold on a sec. - Help.
That camera was paying for this expedition.
Alex...
...I'm sorry.
- Sorry. - Yeah.
There's a current.
Grab some food. You two keep an eye out.
We'll rest for 20.
I'm getting a little worried.
Gangrene might be setting in.
I don't think the antibiotics are working.
What should we do?
Not sure we can do anything.
- Maybe I should talk to him. - Never seen Jack like this.
He's completely losing it.
We're five miles in.
- We're not going back. - That's for sure.
Jack's the most experienced one. If anyone can get us out, it's him.
Oh, come on, Charlie. We don't know where the hell we're going.
How you doing?
Jack...
...I'm worried about you.
Briggs is gonna be a problem.
You know that, don't you?
I can't save them, Tyler, if they don't trust me.
I'm gonna need your help with that.
You understand?
Okay.
All right. Let's get in the water.
Let's not get too spread out.
Everybody should be in the water by now.
I'm in now. Top and Tyler are right behind me.
- Top, if Jack gets any worse-- -i know.
Let's hope it doesn't come to that.
The current's pushing us up.
Yeah. I feel it.
Looks like it's pretty choppy up there.
All right, listen up. Secure all your gear.
Jack, we don't know where the rapids go.
What do you wanna do? Go back?
She's right. We should find another way.
This is the goddamn way!
- I'll go first. - Yeah, get going.
All right, Dr. Nicolai, you're coming with me.
You'll be fine, all right? Come on.
Tyler, you take Kathryn. Let's go!
Briggs, Charlie! Go now!
Jack!
Dr. Nicolai! Here!
Now put your goggles on and hang on to me.
Here we go.
Your brother's got a serious death wish.
Hey, listen to me. You have to trust him, okay?
We will get out.
It's okay. You'll be fine. Come on.
I'm stuck.
- What is it? - Tyler, something has me.
- Cut your harness free. - Tyler!
- Kathryn, the current's too strong. - Ty, I'm stuck.
- I can't get back! - Ty!
- Kathryn! - Tyler!
Tyler!
My God!
Tyler!
Help me!
What happened? You okay?
- Something had me back there. - You hurt?
I'm okay. I'm okay.
There's something in the water.
Oh, shit. It's some kind of eel.
Does anybody have eyes on Dr. Nicolai or Charlie?
Yeah, I got Charlie and Kathryn.
Nicolai's wracked up on the rocks above the falls. He's in bad shape.
All right, flare's coming up. Top.
I see them.
Yeah. Looks like a couple hundred yards.
All right. Come on. Come on.
Alex, you all right?
- Well, that was a great idea. - You're alive, aren't you?
Jack.
- Everyone all right? - Yeah.
Stick close together.
That's Dr. Nicolai. Top, light another one.
I'm gonna go after him.
Help me.
- Nicolai? - I'm here.
Nicolai!
- Nicolai! - Everybody stay put!
Nicolai!
- We have to help him. - Everybody in a circle.
- Backs to center. - We can't stay here.
We have to help him. Nicolai!
Dr. Nicolai?
We can't just sit here. There's gotta be a shore close.
Nobody's going anywhere until Jack gets back.
What was that? You hear that?
- Oh, shit! - What?
What the hell was that?
- Get back in a circle. -I can't take this!
God!
Jack.
Nicolai!
It's over.
Let's get the hell out of the water.
He said he didn't wanna go deeper, Jack. He was your responsibility.
He said he didn't wanna go deeper.
It's over, Kathryn.
There's a ledge here. We can walk.
- What the hell is that? - Echolocation.
This thing can see us as easy as a bat sees a moth...
...in complete darkness.
Wait here.
I'm gonna scout ahead.
It's a strong current, Kathryn. It's definitely worth a try.
Yeah.
That's gotta come up on the surface.
I'm not sure I like the idea of deep water right now.
Tyler.
We're going up this wall.
This is the main water flow. We just follow it out of the system.
At the top, we'll secure ropes and the rest of you will come up on ascenders.
Jack, I'm the best climber. I'll go first.
Nobody's climbing anywhere.
There's a huge exit sign here in front of us.
You don't have a goddamn clue what's going on.
None of you do.
It's a trap.
The wall is the safest option.
- Jack's right. I'll go. - I said, no.
Let's go.
You see that?
That's where we're going.
- I'll route the left. Let's do it. - All right.
A little insurance for you guys.
We bored out these propane valves to give you a flame...
- ...for about four or five feet. - Yeah?
Scare anything that comes close.
There's enough for a couple blasts.
- Kim, give me a hand with this. - Yeah.
Jack's ill, Tyler. He's not fit to lead anymore.
He's not the man we started with. You know that.
He's my brother.
Charlie!
- I told you no! - Hey, be careful!
Get the rope.
Get your ass back down here, Charlie!
I'll be all right.
That girl's quick, man. Get the rope, Top.
- Okay, I'm on belay. - On belay.
Let's find a route. Let's go.
You hooked in? Top, you got it?
Damn, that girl moves fast.
Be careful up there, Charlie!
Charlie!
Charlie, you got good holds to your right.
Keep moving right.
- I think she's over the edge. - All right!
How are we gonna follow that?
She just went over the bump. She's good.
I can't even see her.
I got it here. Just keep feeding it out.
There we go.
- How does it look? - Okay.
How's it holding, Tyler?
Looks good, buddy.
Safe!
Talk to me, Charlie. What's going on?
Is the line set? Ready to climb, Charlie.
Charlie?
Jack, I'm over the edge.
I can feel a draft.
- What's going on? - I'm going, Top.
Go for it.
What's going on, Charlie?
You safe, Charlie?
Charlie?
Charlie!
- Charlie, talk to me. - Damn it, Top.
- You see her? - Charlie!
Get me down! It's up here!
Get that rope free.
- Jack! - I'm going up.
- Hurry, Tyler. - Come on, guys. Come on.
Get me down!
Charlie!
They fly! They freaking fly!
Charlie!
There's enough secured rope to make it to the opening.
What's happening to you?
As long as we stay together as a group, we can hold them back.
I think I know now.
- It's a parasite. - That's from a parasite?
It mutates the host...
...so they can both survive down here in this environment.
- That's what's gonna happen to us? - I don't know, Alex.
I'd say...
...it entered your bloodstream through one of your cuts.
Jack, it's affecting your nervous system.
So the other cavers...
...it happened to them.
- So, what, it just ate them? - No.
They weren't eaten by the creatures.
They are the creatures. Right, Jack?
And now there's nothing human left.
- They're enjoying this, Kathryn. - So now you understand them, Jack?
Jack.
Jack, you're gonna be fine. You've gotten us this far.
"Got us this far," Tyler?
Come on. He got Charlie and Dr. Nicolai dead.
That's what he got.
No. No more.
Let's follow what we know. The river's the way out.
Kathryn's right. I'm with her.
Who else is coming?
Alex?
If you ever wanna see the sun again, you should follow me now.
This is bullshit. We have to stay together.
Tyler, look at him.
He's not human.
We need you with us.
Tyler.
Good luck.
Fine. Let's get in the water.
Tell me we're doing the right thing.
Don't stop believing in him, Ty.
It's getting cold.
Where to?
Down.
You sure?
Yeah. Down.
- My lead. Let's go. - Yeah.
You okay?
Yeah, it's solid. Off rope!
- Tyler! - Tyler.
Top, cover!
Shit.
Hold on, Top!
Top? Top, you all right?
My leg.
- Can you walk? - I don't know.
Oh, shit.
Looks like the rebreather punched a hole through the ice.
Yeah.
Smells like methane.
Some kind of killing ground.
It's just like Nicolai's mosaic legend.
That means there's gotta be an opening close by.
Top. Tyler.
You see the light?
- Yeah. - There's cold water coming up.
- That's the way out of here, Tyler. -I think you're right.
It must have been a dry passage.
Jack?
Jack.
Jack, what's happening?
Top.
What's going on?
Jack.
You two are getting out. I'm going back for them.
You're in no condition.
- Top can barely walk. I'll go back. - Put your gear on and get in the water.
I'm not getting in the water. You're not going back.
Mac!
He's right.
Now, come on, Jack. You led us here. You were right.
But I'm doing this now. I'm going back for them.
This is the way. We walk until it opens up again.
Run.
Shit, we got company.
He must have followed us in here.
This thing has got to have a weakness.
- Yeah. Everything's got a weakness. - Where is it?
It's moving.
Top!
It took one of the rebreathers.
He's playing with us.
Kathryn!
Briggs!
Kim! Kathryn!
- Briggs! Briggs! - Help!
- Briggs! come on! - No!
Come on!
Hold on! Damn it! Come on!
No!
- No! - Shit.
Tyler...
Briggs.
- Kathryn. . .. - Where?
Sorry.
Go.
- Go. - No.
Briggs!
Shit.
Tyler.
Oh, my God. Are you all right?
What happened? Why did they leave?
Sound waves. They retreat from the pulse.
- Doesn't last long. They come back. - We found a way out.
Jack was right.
Any others? Briggs?
No. No. He didn't make it.
- Where's Kim? -I don't know. We got separated.
Shit.
All right, come on. This way.
This is it. You ready?
You can make it.
Yeah.
All right.
Let's go.
I got you. It's gonna be fine.
Watch your head.
Tyler.
You've gotta go under.
Come on, Kathryn. Breathe.
Are you all right?
- Alex. - We gotta go, they're coming this way.
- Look, I can't go back in the water. - Come on.
The way out's next to an ice vein. This has to connect.
Come on. Let's go.
All right.
They gotta be here somewhere.
But where?
Jack.Top.
Quiet.
Kill your light.
Where's Briggs?
They're watching us.
They see with sound.
And the steam, it's confusing them.
They took one of our rebreathers, but they've left us alone since.
- They're waiting on something. - There were more right behind us.
We should get in the water now.
Look, this works for a while.
We have to split out those tanks, the air and the oxygen.
It won't last long, but it's our only choice.
We need the other rebreather, Tyler.
- You see it there? - Yeah.
I'm gonna go for it. Get the rest of them in the water.
Okay.
All right, Top, start breaking down that unit.
Kathryn, you and Alex will have to buddy-breathe from the air tank.
Top, that's gonna leave you with the oxygen.
- No regulator. - Cool.
Jack.
I'll cover you with the mapping gun.
All right. Let's go. Let's get out of here.
Let's go. Come on.
Alex!
Tyler!
Jack!
Tyler, behind us.
Tyler!
Jack, there's another one!
Jack, no!
Go!
Get in the water.
Come on, mother--
No!
- You gonna be okay, Tyler? - Yeah.
Take care of yourself, man.
Bye, Kathryn.
Thank you.
- Travel safe, okay? - All right.
Tyler?
I'm sorry.
You're thinking about him.
Yeah.
You said that parasite was changing him.
I mean, he never could have survived out here, could he?
At first...
...I thought it could only survive in a cave environment.
But now I'm not so sure.
I think it wants to get out.
No.
Excuse me.
Hey.