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.

Chinese sleuth Charlie Chan discovers a scheme for the theft of government radar plans while investigating several murders.

After one member of their group is murdered, the performers at a burlesque house must work together to find out who the killer is before they strike again.