Charles Boyer stars as Pepe Le Moko, a criminal whose exploits have made him notorious throughout Europe and for two years has been living in Algiers within a stone throw of the police headquarters in a Kasbah, a city within a city. Pepe Le Moko is the king in the Kasbah and though it would be easy for the police to arrest him it would be impossible to get him out. While ever he stayed in the Kasbah Pepe would be safe. A French official insists that he be captured, but sly Inspector Slimane (J. Carrol Naish) knows he need only bide his time. When Pepe Le Moko meets Gabby (Loretta Young) the beautiful wife of an influential French politician who is on business in Algiers, they fall in love and the safety of the Kasbah comes to be his prison.