Near the Millau viaduct, the body of Paul Gasteuil is discovered wearing a devil’s mask. This strange scene seems to be linked to the legend of Sainte-Enimie and intrigues Alice Nerval, the Millau gendarmerie captain in charge of the investigation.

To unravel the crime, Alice agrees to team up with Adrien Nerval, her father-in-law, also a captain who was sacked six months earlier for personal problems…

The situation is made all the more tense by the fact that Adrien has had no contact with his son Jérémy for years … who would be furious if he found out who his wife’s new colleague was.

Will Alice be able to navigate between this particularly complex investigation and a volatile family situation?