 General Bierbeau sends his weakling son, Pierre, to French Morocco to fight Arab insurgents (the "Riffs") in the hopes that this will toughen him up. He soon becomes the Riffs  leader and assumes a secret identity: "The Red Shadow." Pierre is still regarded as a weakling by the French troops because he always seems to let the Red Shadow slip through their fingers. When Pierre s sweetheart, Margot, visits the French garrison, she succumbs to the Red Shadow s charms.