Inspired by a true story, the film follows Captain Alexi Vostrikov (Harrison Ford) who, at the height of the Cold War, is ordered to take over command of the nuclear missile submarine K-19, pride of the Soviet Navy.

His assignment: prepare the K-19 for sea and take her out on patrol - no matter what the cost.

But problems with the K-19 arise that may lead to a core meltdown and explosion that will certainly kill all aboard, and possibly trigger a nuclear war. Vostrikov must choose beteween his orders from the Kremlin and the lives of his men.