Astrid and Raphaëlle return for a new round of mysteries, more mysterious than ever! Parapsychology, African fetishes, mathematical theory, the guillotine, a Homeric trial, and even the Devil himself… Our investigators will have their hands full as major upheavals occur in their personal lives. How will Raphaëlle handle the consequences of the poisoning she suffered? Traumatized and diminished, she will have to reinvent her daily life as well as her bond with Astrid and Nico. Devoted more than ever to her best friend, Astrid realizes she is being followed by a mysterious stranger. She soon discovers he is connected to Tetsuo's family. Is he really who he claims to be? The moment of truth has arrived for our two investigators' couples.