A young architecture student is murdered in the hall of the Gare de l'Est. The investigation of Revel and Melanie Rousseau tells them that he had been selected among the ten finalists in a large architectural project for La Défense. The favorite of the contest is now Xavier Michel Corbin, a famous architect who seemed to exert a strange fascination for the young man who was murdered.

A triple murder was committed within minutes. Vincent Revel and Mélanie Rousseau are responsible for this delicate investigation. Soon, they trace a BAC policeman, a man with personality disorders, who could be the perpetrator of the massacre. This discovery deeply disturbs Revel, and for good reason: he knows the suspect well since it is his half-brother, with whom he has not had any contact for quite a few years. He is shocked to find that this one has the same pathology as their mother ...