Down . . . Down . . . Down . . . into enemy waters with the fightin' hellcats of the U.S. sub pack !

Captain Casey Abbott commands an American submarine in the Pacific during World War II. When a perilous mission to retrieve a new Japanese mine for study goes awry, he's forced to abandon a likable combat diver. Abbott's orders to leave a man behind appear to be justified, but his second-in-command believes he had ulterior motives: