When Mario, a bad boy, is released from prison, he plans to live honestly with his wife Geneviève. But the latter has not waited for him and Mario, out of spite, accepts to work as a tout for Mr. Charlie, the boss of a white slave trade gang. His first assignment consists in seducing Michèle, a Montmartre nightclub singer and hostess, into signing a contract for Tangier. The young woman, however, who does this job only to support her young sister Danièle, falls for him and he for her. From then on Mario, without betraying himself, does his utmost to save Michèle -and Danièle for that matter - from the clutches of the gang.