Kevin Lorin, just 18 years old, has become a high-flying con artist, a potential Arsène Lupine. While the police intervene in one of his scams on the Basque coast, he gives up running and, to everyone's surprise, surrenders. This early retirement takes an unexpected turn when the commissioner recruits him for a very special infiltration of a murder case. After this "fun" experience, he only has one idea in mind: becoming a police officer.