"Rich" Richardson (Clark Gable) is a hard-driving, dedicated submarine officer with a single-minded purpose - to seek out and smash the Japanese destroyer he believes sunk his former ship. Given a new command, Richardson drills his men to the point of mutiny as he relentlessly trains them for the battle ahead. At last, word comes of the destroyer's position, and disobeying orders, Richardson finally confronts his foe, unaware that an even greater enemy lurks nearby, one who's been targeting him for a watery grave.