Three men with a penchant for gambling on the horses soon find themselves in trouble because of their addiction. Pierre (Michel Piccoli) is the math whiz who uses his talent for picking the winners. Charles (Michel Galabru) is the wealthy scrap-iron magnate who has embarrassing evidence on many prominent political figures. Loic (Jacques Dutronc) is the aspiring politico who seeks to further his career by any means possible. Charles approaches Loic and asks his political party for a loan in hopes of fixing an upcoming race....

In 1951, in Saint-Germain-des-Prés, the private detective Nestor Burma was commissioned by an insurance company to find stolen jewelery. The deal seemed easy and Burma got an appointment with a well-known black trumpet player in the neighborhood who could provide him with information. But the musician does not come and we find him murdered. The investigation becomes more complicated and Nestor must find an alibi so as not to be suspected of the crime.