Inspector Maigret is assigned to monitor the arrival in Paris of an international conman known as Pietr the Latvian. At the train station, the case immediately becomes complicated when a man matching Pietr’s description is seen, while another man—who closely resembles him—is found dead in a train compartment.
Maigret’s investigation leads him across Paris as he tries to uncover the truth behind the double identity. He gradually realizes that Pietr may be using multiple identities to evade the authorities and reinvent himself.
Rather than relying on physical evidence or action-driven investigation, Maigret solves the case through careful observation and psychological insight. The novel highlights themes of identity, deception, and human behavior, and introduces the distinctive investigative style of Inspector Maigret.