Out of prison after a five-year stretch, jewel thief Tony (Jean Servais) turns down a quick job his friend Jo (Carl Mohner) offers him, until he discovers that his old girlfriend Mado (Marie Sabouret) has become the lover of local gangster Pierre Grutter (Marcel Lupovici) 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.