Michel, a solitary young man in Paris, decides to become a pickpocket, driven by a mix of compulsion and curiosity. He begins practicing his craft in public places such as busy streets, Metro stations, and racetracks. With meticulous planning and deft hand movements, Michel becomes increasingly skilled. His actions catch the attention of the police, leading Inspector Antoine to suspect him, but Michel's techniques prove elusive. Throughout these activities, Michel's life intersects with his few connections, including his bedridden mother and an old friend named Jacques, who disapproves of his choices. During one visit to his mother’s apartment, he meets Jeanne, a neighbor who cares for his mother.

Michel's dedication to pickpocketing intensifies as he finds a mentor in a seasoned thief who teaches him more advanced techniques. The two work together to execute increasingly audacious thefts. Despite the danger of exposure and the growing pressure from Inspector Antoine, Michel is drawn deeper into the life of crime. Simultaneously, his relationship with Jeanne begins to develop, introducing emotional complexity to his otherwise detached existence. However, Michel’s internal conflict and reckless ambition set up a precarious trajectory that threatens everything he holds dear.