Julie (Crawford), a cafe entertainer in a town near the Devil’s Island (French Guiana) penal colony, meets Verne (Gable), a prisoner on wharf duty. Verne escapes and goes to Julie's room, but is apprehended after Mssr. Pig (Peter Lorre) reports him, and he is returned to prison. Julie is fired for consorting with a prisoner. At the prison, Moll (Albert Dekker) has masterminded a jailbreak and takes Cambreau (Ian Hunter (actor)), Telez (Eduardo Ciannelli), Hessler (Paul Lukas), Flaubert (J. Edward Bromberg), and Dufond (John Arledge) with him.