Emile is a steelworker in a car factory ;a confirmed bachelor going on fifty, he leads a peaceful life .One night, he is woken up by a burst of machine gun fire. The cafe in the corner of the street has been burglarized.A distraught young girl rushes into his apartment building and hides in his room .When the police make a search, he makes her out to be his lover for the night.Madeleine tells her about her sad past : she has severed all links with her parents ,she's an unwed mother and in the underworld's clutches. Emile sends his protegee to old mommy Dupont's place ,in the suburbs of Paris.