Open the door and they die.
Six experienced saturation divers report for a new job – repairing pipelines on the sea bed. They are locked inside a chamber and then lowered to the sea floor while a team back on the surface monitor them night and day to keep them alive. Calm and professional, the divers know that rapid decompression would be fatal and so they work in shifts, breathing helium, and surviving in hot, close quarters.
Until one of them is found dead.
Remain inside and they’re at the mercy of each other . . .
With four days of decompression to go before the locked hatch can be safely opened, they can do nothing but wait. And then another diver is found unresponsive.
Will any of them survive to the end, or will paranoia, exhaustion, suspicion and extreme pressure destroy them all?