On a Marseille film set, a street urchin who has been hired as an actor is suspected when both a star and a baroness are robbed.With the help of the boy's neer do well friend the real crooks are tracked down.

The action takes place on the coast of the eastern Pyrenees near the Spanish border. Mario Balducci escaped from prison, after settling his account with his former accomplice who had given him away, he joins his ex-mistress, Mado, a bellowing singer who he asks to help him get to Spain.