Henri Bencolin emerges from his retirement to investigate the inexplicable murder of a Parisian courtesan found dead in a room containing four potential murder weapons. The protagonist must navigate the complex social circles of Paris to identify which of the four items was the true instrument of death. He faces opposition from elusive suspects and the logical constraints of a crime scene designed to confound investigators. The narrative utilizes a third-person perspective to track Bencolin's analytical process as he deconstructs the physical evidence left behind by the perpetrator.

Readers frequently highlight the intricate puzzle-solving elements that define this entry in the Bencolin series. Discussion often centers on the author's ability to manipulate the reader's perception through the use of multiple potential murder weapons. Critics note the atmospheric depiction of Paris which serves to heighten the tension surrounding the central crime. The pacing is described as methodical, favoring logical deduction over rapid action sequences. Many enthusiasts of the genre appreciate the classic structure that challenges the reader to solve the mystery alongside the detective.