This wartime drama is set aboard the USS Corsair, a submarine on active duty. Against his wishes, Ward Stewart is made executive officer and given just days to prepare. Before boarding he meets schoolteacher Jean Hewlett, and is captivated. He plans romance, unaware that she already has a sweetheart: Dewey Connors, Commander of the Corsair and Stewart's boss. The men embark on a dangerous campaign to destroy a secret Nazi base, but will their rivalry imperil the mission?