In 1930s Marseille, France, gangster Siffredi (Alain Delon) wants to locate his old girlfriend when he gets out of jail. But Siffredi's old flame is with another gangster, Capella (Jean-Paul Belmondo), and a fight ensues. After cooling off, the two men decide to become partners, and embark on a slow but steady quest to control the criminal underworld. They start with fixing fights and horse races but eventually move into more dangerous territory that puts their lives at stake.