Out of prison after a five-year stretch, jewel thief Tony turns down a quick job his friend Jo offers him, until he discovers that his old girlfriend Mado has become the lover of local gangster Pierre Grutter during Tony's absence. Expanding a minor smash-and-grab into a full-scale jewel heist, Tony and his crew appear to get away clean, but their actions after the job is completed threaten the lives of everyone involved.
Véronique gives a mathematics lesson to a dunce who answers the prepared questions with disconcertingly sound answers.
Picked up by a beautiful motorist, jobless hitchhiker Pierre (Hossein) is subsequently romanced by the girl. Immediately thereafter, however, she dumps him, attempting to run him over as a final insult. Memorizing her license number, Pierre pursues the enigmatic motorist. Arriving at her home, Pierre is met by two young ladies (Marina Vlady and Odelle Versois), either one of whom might be the woman he's looking for.
