Jean-Paul Belmondo is starring as the boy Michel who is trying to look like Humphrey Bogart. On his way to Paris he steals a car and murders a police officer. Once in Paris, he establishes a relationship with the American Patricia. Sooner than expected she turns out to be a horrible femme fatale. The couple does nothing all day but stealing cars and making love. Meanwhile the police is tracking Michel. Michel starts taking more and more risks...