Julian, 25, and Louis, 12, are two brothers who work and live on a barge in the centre of Paris. They transport gravel and resort to petty crime to make ends meet. They have grown up alone and now they are inseparable, wedded to a life on the river. A receiver of stolen goods offers them the opportunity of a lifetime, to steal a painting by Manet from the Musée d'Orsay. Louis takes charge of the theft and, against the odds, he succeeds in removing it from the gallery and taking it aboard his barge. Rosalie, a museum guard, follows Louis to his home and confronts him. After a fight, the two brothers secure Rosalie in the hold of their boat and make a quick getaway. Later, Rosalie emerges from her hidey hole and makes the brothers an unexpected offer...