When Maigret receives an urgent call from his friend Dr. Pardon he responds immediately, despite the late hour; it seems that the doctor has just treated an apparently wealthy woman for a suspicious gunshot wound, but before he could notify the authorities she diappeared with her companion. The doctor's story gains some perspective when the same woman turns up at the house on Avenue du Parc-Montsouris where Felix Nahour has just been found - shot to death. This is a masterful exploration of the twin passions of love and hate as they mingle in the shadowy mind of a criminal.