When Pierre Dormain and his wife die in a train disaster, the custody of their children Simon and Dédée is transferred to their uncle Jean de Mareuil. The uncle is persuaded to let his servant’s mother take charge of their care. The money she receives for the care is spent entirely on alcohol and the children have to work hard for their meal. Eventually the children run away from home and roam the streets of Paris. When one of the children is seriously injured after an accident, the uncle finally realizes he has made a grave mistake.