Although suspected and hunted down by policeman Sherlock Coco and inspector Hector, the Pieds Nickelés (Croquignol, Filochard and Ribouldingue) manage to save the legacy of Monsieur Miradoux, who will be very grateful to them.

Tongues start to wag after a famous Parisian music hall dancer is rushed to hospital after being found poisoned by arsenic at the Concert Mayol.

Young Monique leaves the preventorium where Doctor Delaunay has lovingly cared for her. A painful return. Her mother Denise lives with Eugène, a handsome, disreputable young man who's easy to please and, on occasion, won't hesitate to steal. He hangs around Monique, excited by her freshness, until the day he is shot on suspicion of the disappearance of a mobster. Monique is reunited with Dr Delaun...

Jean-Louis, Danielle's fiancé, a nurse, becomes blind following an explosion in the mine where he works. Coming from Lyon, Doctor Coudray, whose natural son Gilbert - who loves Danielle - dies while helping his father threatened by the person responsible for Jean-Louis' accident, will work to restore his sight.

A rich businessman, threatened by his pregnant mistress, decides to make him marry a man who falls in love with his daughter.