Police detective Leonard Diamond (Cornel Wilde) has two dangerous obsessions. He's on a reckless, hell-bent crusade to bring down smooth and sadistic gangster, Mr. Brown (Richard Conte) and wracked by insatiable desire for good-girl-gone-wrong Susan Lowell (Jean Wallace), Brown's captive lover. In mortal terror, Susan is helpless to escape from the lust-filled nightmare of her life. Meanwhile, Brown's lieutenant-in-crime, McClure (Brian Donlevy) plots with cruel hoods Fante (Lee Van Cleef) and Mingo (Earl Holliman) to overthrow their boss. In Brown's unforgiving world, however, defection and disloyalty are punishable by cruel and unusual death.