Clandestine Paris.

In the elegant nightclub of Corsican Luciano, known as Lucky, "Les Naturistes", big sums are gambled at the Longchamp races. Lucky not only "welcomes" the new dancers, he also collects the stakes entrusted to him and personally plays the horses recommended to him by Max, a former convict. But Bramati, Lucky's ex-partner, doesn't forgive Max for double-crossing him and has him shot.