Snakes in a sub. James O'Neill (Perry) is being forced into retirement and he's not happy about his last assignment. Using a decommissioned sub, he has to evacuate scientist Andrea Swanson (Allen) and her assistant Jake (Mandylor), plus her cargo of mutant snakes, when the military project she was working on is shut down. The sub is attacked by the Chinese and the snakes get loose and start eating the crew.