Mathias, a young musician, has just left his wife and baby. He finds himself in Paris, near Saint-Ouen. He rents a hotel room and announces by phone to Clémentine, his wife, that he will not be coming back. She is not surprised by this news. She has known for some time that Mathias frequents Louise and that he came to join her in Paris. Clémentine accepts everything with a kind of resigned grace. Mathias leaves the prey for the shadow and will understand it at his own expenses.