A woman without stories is found dead on a bench in a park, victim of a sting poisoned by the venom of an exotic snake. Astrid and Raphaëlle embark on the case and soon find themselves on the trail of a dangerous mafia hitman who had not been talked about for years. Why did he come out of the shadows again? Did this woman die by accident or was she involved in illegal activities? The two investigators have a hard time to get the truth out in the open. As always, Astrid's extraordinary sagacity is of great help to Raphaëlle...

Maxime Rivière, a friend of Commissioner Bachert, is the victim of a recurring nightmare concerning the murder of the Tibetan monk. Astrid makes the connection with the unsolved murder of the llama Tulku Lingpa, on May 20, 1996, in a monastery in Île-de-France. On their way there, the commissioner, who turns out to be a Buddhist, Raphaëlle, Astrid and Nicolas discover disturbing elements that question the guilt of the perpetrator of the murder, a drug addict who was prowling in the nearby forest. According to Raphaëlle, the crime was committed inside the monastery.