Granier (Claude Brasseur) is a small-time hood, doing jail time for his deeds. While there, he makes friends with a much bigger criminal, and promises to help him out when they leave prison. The big-time hood is killed soon after his release from prison, but by that time Cave has learned enough to blackmail his accomplices, who are all important men in their town. He also manages to win the affection of the gangster's girlfriend.
Source : allmovie.com