Pepe Le Moko (Boyer) is a notorious thief, who, after his last great heist, escaped from France to Algeria. Since his escape, Moko became a resident and leader of the immense Casbah, or "native quarter", of Algiers. French officials who arrive insisting on Pepe's capture are met with unfazed local detectives, led by Inspector Slimane (Calleia), who are biding their time. Meanwhile, Pepe begins to feel increasingly trapped in his prison-like stronghold, a feeling which intensifies after meeting the beautiful Gaby (Lamarr), who is visiting from France. His love for Gaby soon arouses the jealousy of Ines (Gurie), Pepe's Algerian mistress.