In this satire of film noir, Lou Peckinpaugh (Peter Falk) is a San Francisco detective in the boozy, wise-cracking tradition of Humphrey Bogart in The Maltese Falcon. A suspect in the murder of his own partner, Lou hopes to solve the crime and exonerate himself before the cops haul him in. Meanwhile, he takes a case involving stolen diamonds, and gets reacquainted with his old flame, Marlene DuChard (Louise Fletcher), who's on the run from the Gestapo.