""...a readable tale that is a joy to read from beginning to end."
Maigret along with an Examining Magistrate, a Deputy Prosecutor and a Clerk to the Court, are called to the Pont Marie, a bridge that connects the Île Saint-Louis to the north bank of the Seine. A tramp who sleeps under the bridge has been beaten and thrown into the river in an attempt to murder him. Due to the three men's distaste at the crime, they quickly leave and Maigret is left to investigate. He had been rescued from the water by a Belgian barge owner called Jef van Houtte, using a gaff .
The tramp's nickname, he soon discovers, is 'Doc', and he lies unconscious in hospital, unable to help. But Maigret soon discovers his identity. He was indeed a doctor at one time, from the city of Mulhouse, and his name was Francois Keller. Maigret investigates further, delving deep into the man's past, but is unable to find a connection between Mulhouse and the attempted murder. Along the way, he is sidetracked by a dead dog, a suspicious nurse in the Hôtel Dieu where the victim lies, and, eventually the realisation that Keller may not want to divulge who it was who attacked him.
But gradually a story emerges, and Maigret feels he has cracked the case. However, the outcome is not to his liking...