The movie follows the rise and fall of a con man—a story that begins and ends at a seedy traveling carnival. The carnival's barker, Stanton "Stan" Carlisle (Tyrone Power), is fascinated by everything there, including a grotesque Geek show, who prompts an observation from Stanton that he "can't understand how anybody could get so low." Stanton works with "Mademoiselle Zeena" (Joan Blondell) and her alcoholic husband, Pete (Ian Keith). Once a top-billed vaudeville act, Zeena and Pete used an ingenious code to make it appear that she had extraordinary mental powers, until her attentions to other men drove Pete to drink and reduced them to working in carnivals. Stanton learns that many people want to buy the code from Zeena for a lot of money but she refuses to sell; she is saving it as a nest egg.