Superintendent Maigret arrives in the small fenland town of Saint-Aubin-les-Marais after being asked by a friend to help a man accused of murder, only to meet with hostility and silence from the townspeople. Matters are not improved when he encounters an unpleasant former colleague nicknamed Cadaver, sacked from the police force for corruption and now working as a private sleuth. Cadaver seems to be doing everything in his power to obstruct Maigret's investigations, but who has employed him? Maigret soon finds himself involved in a case that may ruin the very people he has come to help.
Asked to help a friend's brother-in-law accused of murdering his daughter's lover, Maigret finds himself plunged into an atmosphere of animosity. Also, an old enemy - an ex-police officer nicknamed "Inspector Cadaver" - seems to be obstructing Maigret's investigation.
