Maigret has been interrogating a mysterious Dane, Carl Andersen, for hours without a confession. Why was the body of a diamond merchant found in his car at his isolated mansion? He's either innocent or a very good liar. What does his beautiful but vulnerable sister know? And what compels everyone at the Three Widows Crossroads to be so secretive? Maigret sets out to find his killer which ultimately leads to a thrilling climax.