In 1932, In France, fourteen year-old runaway orphan Yves Tréguier is sent to a reformatory after several attempts to travel to New York as stowaway on a ship. In prison, Tréguier is protected by the aspirant mechanic Blondeau against the bully rascal Molina. He befriends the upper-class teenager Marcel "Fil de fer" Morand who was sent to the institution by his stepfather and misses his mother (Carole Bouquet) and his piano. Tréquier unsuccessfully tries to escape from the brutal reform school and invites Blondeau to go with him.
—Claudio Carvalho, Rio de Janeiro, Brazil