Sam Spade is a private detective in San Francisco, in partnership with Miles Archer. The beautiful "Miss Wonderley" hires them to follow Floyd Thursby, who she claims has run off with her sister. Archer takes the first stint but is found shot dead that night. Thursby is also killed later and Spade is a suspect. "Miss Wonderley" is soon revealed to be an acquisitive adventuress named Brigid O'Shaughnessy, who is involved in the search for a black statuette of substantial value. Some other dangerous people are after this statue and lady O'Shaughnessy begs for Spade's protection, but tries to keep him in the dark, revealing as little as possible to him.