In the Marais district in central Paris, somebody is going round murdering young women. Maigret is called to investigate.

For some time now, women coming home at night have been savagely murdered by a mysterious serial killer. Inspector Lagrume thinks he has found the culprit in the person of Barberot, a local butcher. But Maigret, who takes over the investigation, is not convinced. Deep inside himself, he knows the murderer is still at large. But how to trap him?—Guy Bellinger