Everybody at the Quai des Orfevres knows that murders rarely happen on Mondays, but one cold and rainy Monday, Maigret is called in on a murder in the Third Arrondissement. It turns out to be one of the knottier cases for Maigret to untangle because the murder victim himself is a bit of an enigma. Lion’s share of the story is devoted to Maigret and his team trying to uncover who Louis Thouret really was at the time of his death. How did this humble shopkeeper and hen-pecked husband end up knifed in the back in a quiet cul-de-sac off the Boulevard Saint-Martin?
Maigret broods over who Monsieur Louis was and came to be,
In the old days he had been particularly struck, even one might say romantically stirred, by the sight of those who, discouraged and defeated, had given up the struggle, being swept along willy-nilly by the great surging tide of humanity.
Since then, he had come to know many such people, and it was no longer them whom he most admired, but rather those just one step above them on the ladder, who were clean and decent and not in the least picturesque, and who fought day in and day out to keep their heads above water or to nurture the illusion, or perhaps the faith, that they were alive and that life was worth living.
With his usual distracted but dogged air, Maigret goes about reconstructing the events that lead to the murder. A colorful cast of characters, as well as Thouret’s thoroughly unpleasant wife and daughter, each add a small piece of the puzzle. In the end, the actual killer is barely glimpsed, for by then Maigret himself has moved on.