In a corrupt Alabama town, the law can do little to stop the criminal activities of Rhett Tanner, particularly in the wide-open "red-light district" area. Most of the police do not even try, being on Tanner's payroll.
When an employee at an illegal gambling den dies suspiciously, her sister, Nancy, looks into the situation and falls for Johnny O'Clock, a suave partner in the underground casino. Selfish and non-committal by nature, Johnny slowly begins to return Nancy's affection and decides to run away with her, but conflict within his business threatens their plans. As Johnny tries to distance himself from the casino, his shady past comes back to haunt him.
Jackie Cogan is an enforcer hired to restore order after three dumb guys rob a Mob protected card game, causing the local criminal economy to collapse.
A newspaper publisher, wanting to prove a point about the insufficiency of circumstantial evidence, talks his possible son-in-law Tom into a hoax in an attempt to expose ineptitude of the city's hard-line district attorney. The plan is to have Tom plant clues leading to his arrest for killing a female nightclub dancer. Once Tom is found guilty, he is to reveal the setup and humiliate the DA.