Le secret de la grotte (2023)

The Pont d'Arc. Young kayakers paddling down the Ardèche stop a few meters from the Pont d'Arc, in the town of Vallon-Pont-d'Arc, and discover the body of a murdered man, kneeling in a posture of penance. Gendarmerie Commander Vernon assigns the investigation to Captain Riad Lekcir and his counterpart Manon Ferret-Duval, from the Grenoble research section. But cooperation between the two officers looks set to be very difficult: in 1997, around the time the Chauvet Cave was discovered, Kamel, Riad's older brother, was arrested and accused of killing Manon's parents, when she was eight years old, and died by suicide while in custody. The murdered man, Paul Cousin, is in fact one of the three discoverers of the Chauvet Cave and the president of its museum. The investigation reveals that he was killed with a knapped flint blade dating back 36,000 years—the age of the cave—and resembling eight other blades kept at the museum. Some time later, Xavier Berg, who was also part of the trio that discovered the cave in 1997, is found murdered, likewise kneeling in a posture of penance, facing the cave. The mystery deepens further when the two captains discover that the cave's third discoverer, Serge Locatelli, died of a tumor three months earlier, leaving a letter in which he reveals that the young Kamel Lekcir was with Cousin, Berg, and Locatelli when they discovered the Chauvet Cave, the day before his suicide. A dark secret links the discovery of the Chauvet Cave, the murder of Manon's parents, Kamel's suicide while in custody, prehistoric flint blades, and the murders of Paul Cousin and Xavier Berg.