A catastrophic event forces the crew of an underwater research base to evacuate into cold and dark waters. Cut off and alone from the surface, no help is coming.

Mary, the determined station commander, leads the survivors on a dangerous journey across the ocean floor to safety. One through perilous terrain and unexplored areas with limited oxygen.

But in the darkness of the ocean, other threats are lurking. With no weapons or any defences, the group will no choice but to face them head-on.