An unknown young women in evening dress is found dead in the streets of Paris. Maigret and Lognon, who has a persecution complex, must work together to investigate the case. No one, however, seems to care or know who this young woman was.
During a stakeout, a police inspector is shot in front of a building with furnished rooms to rent. Maigret moves in and observes the comings and goings of all the boarders.
An unemployed man for several years feigns to his unsuspecting wife that he goes to work everyday. Instead he happily sits on benches all day on the boulevards of Paris. One day he is found stabbed to death and Maigret must find out why.
After a mutilated hand was found entangled in the prop of a canal barge, divers find other body parts, but no head. Maigret struggles not only to identify the corpse but also to find out what happened.
A nervous wife informs Maigret her well to do though often absent husband has been missing for a month without giving any sign of life. She's worried. Could Maigret come to Rouen and investigate she wonders?
Picpus predicts a murder will take place that afternoon and the police arrive late only to find the corpse of Mme Jeanne and an old frail man locked in the kitchen. Who is this man and what is his connection to Mme Jeanne's murder?