Police Lt. Leonard Diamond (Cornel Wilde) is criticized by his superior Capt. Peterson (Robert Middleton) for his obsessive but fruitless investigation of organized crime boss Mr. Brown (Richard Conte). Peterson calls it a waste of the taxpayers' money motivated by Diamond's love for Brown's girlfriend Susan Lowell (Jean Wallace).
Watched at all times by henchmen Mingo (Earl Holliman) and Fante (Lee Van Cleef), and masochistically drawn to Brown, Susan is unable to walk away from him. She overdoses on pills in a suicide attempt and, in her delirium, utters the name Alicia.
Diamond follows up on that new lead, and as he gets closer to defeating his adversary, the arrogant and sadistic Brown retaliates by capturing and torturing Diamond.
Meanwhile Brown's former boss but now humiliated underling, Joe McClure (Brian Donlevy), believing that Brown has gone too far in his personal vendetta against Diamond, tries to enlist Mingo and Fante in overthrowing him.
However, they remain loyal, and, in a chillingly silent scene visually punctuated by flashes of gunfire, they shoot the deaf McClure after Brown removes his hearing aid.
Though superficially a story of good vs. evil, Joseph H. Lewis's film noir presents a complex world, visually captured by John Alton's stark photography, in which the lines between good/evil and love/hate are not always clear.