An underwater cave diving team experiences a life-threatening crisis during an expedition to the unexplored and least accessible cave system in the world.

Josh: Assumption *is* the mother of all fuck-ups.
Josh: [Frank starts giggling uncontrollably] What?
Frank: You remind me of me.
Josh: ...shit.
[first lines]
Dex: Josh? Wow, your old man let you come up for air?
Josh: Oh you're kidding, Dex.
Dex: Oh you're gonna be in the shit.
[big hug]
[last lines]
Josh: I never knew my father, but I found him in that cave. He was a hell of a fella, once you got to know him.
Dex: Josh is his own man. He doesn't take after his dad much.
Josh: What, you mean I'm not an emotional shutdown Nazi asshole?
Dex: [about Victoria's skills in mocking Russian accent] She's strong like bull, smart like tractor.
Frank: I'll see you on the other side.
Crazy George: Could've picked a better choice of words.
Josh: How did you become like this?
Frank: Look... Josh. I know I haven't been anything of a father to you. Alright? I'm not much good out there full stop, mate. That's just the fact.
Victoria: [rejecting ill-fitting diving suit] I'd rather be cold and alive than warm and dead.
Carl: [Talking about Frank] His ass is so tight that only dogs can hear him when he farts.
Frank: Be careful. Please.
Josh: I have control.
Carl: I have control.
[laughs]
Frank: [George falls into the water because of a heavy cough. Frank rushes over] You alright?
Frank: I'm alright!
Frank: Yeah?
Crazy George: Just... taking a leak.
[Long, awkward pause]
Crazy George: And there she goes!