Two young men, Zim and Jean-Pierre, both sentenced for a minor offence, recognize one another when they are released from prison on the same day. One wants to reform, but his friend wants to stay a crook. The first one gets a job and begins improving his life, while the young criminal ends up incarcerated for stealing cars.

Antoine is a violinist in love with sweet Sophie. Problem: his sweetheart is the daughter of the master of the municipal harmony, a stubborn man who swears only by the brass. Never mind: Antoine decides to ask him for his daughter's hand and to win his place at the orpheon. Will the two men be able to get in tune?

Marc Lafarge, 13, is idolized by his brother Thomas, 20, future veterinarian and amateur boxer. Thomas has a soul of justice. Thus, returning home with Marc after a fight, he hits a little thug who has just robbed an old lady.