Alphonse decides to flee to Paris to escape his wife's bad temper. He empties his bank account and finds himself in a nightclub in Pigalle, where the manager confuses him with the American mobster Al Grégor. Frightened by the bandit's reputation for violence, he invites her to drink before having her followed by one of his killers, whose mission is to assassinate him. What was his surprise when, a few minutes later, the real Al Grégor appeared !. It is then a long crossover, a series of interminable imbroglios which begins between the killer, the inspector responsible for arresting the bandit, a famous psychiatrist and the two lookalikes. Al Gregor and Alphonse Ramier, at the end of an eventful pursuit, both find themselves in a madhouse, invaded by pseudo-Romans, American soldiers and all kinds of originals. There is even a famous psychiatrist, Doctor Braque, who investigates the sick in the clinic to see how the director drives them even crazier than they were when they arrived and in doing so earns a lot of money. Alphonse Ramier and Al Gregor will eventually discover that they are twins. Al Gregor precedes Ramier in his native village, where everyone considered him a "minus". Having frightened the population, he prepared the ground so that Ramier could return there and lead a happy married life; his wife now admires, as do the locals, her "terrifying" husband.