A wealthy widow, Natercia, helps Alain, a poor young man, to put together the film he plans to make. They decide to pool their resources to make the project a reality. At the first screening, Natercia realizes that Alain no longer needs her.
Mario di Donati, a deserter from the Italian army, lives in Paris under a false name with Germaine, his French lover. When the latter learns about his hidden past, she feels hurt by Mario's lack of trust in her and she distances herself from him. In despair, Mario surrenders to the law but, at the time of trial, he runs away to join the woman he loves.
Author of the best-selling crime novel Le Poulet se mange froid (Chicken Eats Cold) under the pseudonym Sam O'Connor, Inspector Bourdieux's daughter, Agnès, is unwillingly drawn into the gangster ring by two small-minded young misfits, Dédé and Juju. She's not insensitive to the charms of M. Paul, a false kingpin who is in fact a son of a good family and a thrill-seeker. Planning a heist at the home of one of Paul's snobbish friends, she arrests the real Sam O'Connor, an escaped convict, with the help of her father. Then she and Paul confess their love for each other.
Léo Fardier is a police inspector who goes to prison undercover as a convict. He shares a cell with Mariani, a Corsican mafioso, whose trust he earns. The day Léo leaves prison, the criminal entrusts him with a letter to deliver to his estranged wife. He finds her, and she falls under his spell. The problem is that he, too, has fallen in love with her.