The story takes place in Paris in the 1950s. Four women were murdered on the streets of Montmartre. The cases seemed unrelated, but Inspector Maigret suspected that the four cases were committed by the same serial killer. Maigret was under great pressure to solve the case, so he took advantage of the criminals' vanity and carefully designed a capture plan. As the investigation deepened, Maigret narrowed the list of suspects to three people. The final result was shocking.