After seventeen hours of questioning a suspect without getting him to confess, Maigret decides to release him: Carl Andersen, a Danish citizen living in France, is innocent, unless he is a master of simulation. But then who murdered Isaac Goldberg, a Dutch diamond racer, who appeared in Andersen's car with a gunshot to the chest? Maigret will have to travel to the Crossroads of the Three Widows, a crossroads a few kilometers from Arpajon in which there are only three isolated houses: the villa of an insurance agent and his wife, the gas station of a retired boxer and the decaying Andersen's mansion and his sister, a captivating young woman like a Hollywood actress who lives locked in her room. Maigret will have to overcome his weakness to solve a complex international plot in which everyone involved seems to hide something.