The renowned theatre manager, Paul Rémy, is accused by his general secretary Andrieux of having killed his partner. On the advice of his wife Mona, Paul goes into hiding in a psychiatric hospital to escape from the police. But Andrieux seduces Mona who then turns against her husband.

Henri, the Man from Nantes, comes back to his country after a successful stay in the United States, where he was working for Liski, the drug dealer. With the fame of being a tough guy preceding him, he sets himself to the task of knowing why the French operations were not so profitable - and soon he is master of all links of the organization. He can now get it honed to perfection - or destroy it. Only... the Police are following his every step.