JJ 'Jake' Gittes is a private detective who seems to specialize in matrimonial cases. He is hired by Evelyn Mulwray when she suspects her husband Hollis, builder of the city's water supply system, of having an affair. Gittes does what he does best and photographs him with a young girl but in the ensuing scandal, it seems he was hired by an impersonator and not the real Mrs. Mulwray. When Mr. Mulwray is found dead, Jake is plunged into a complex web of deceit involving murder, incest and municipal corruption all related to the city's water supply.

Four men pull off a daring daytime robbery at a bank, dump the money in a trash can and go their separate ways. Thomas Crown, a successful, wealthy businessman pulls up in his Rolls and collects it. Vickie Anderson, an independent insurance investigator is called in to recover the huge haul. She begins to examine the people who knew enough about the bank to have pulled the robbery and discovers Crown. She begins a tight watch on his every move and begins seeing him socially. How does the planner of the perfect crime react to pressure?