35-year-old Mirage fighter pilot Charlotte Dumas is found dead inside Les Invalides wearing a ring stolen in a notorious unsolved murder of a family in Southern France. A person of interest at the time of the LeGoffs killing, a mechanic in Charlotte's crew who had a relationship with 17-year old Sybil, which her father disapproved of. A successful supplier of the air base, his body was the only one missing after the murder. Convinced that the mechanic did kill the LeGoffs, Jo starts unraveling a setup. The mechanic is actually being framed by Jean Francois LeGoff, who killed his family after his daughter revealed he had molested her when she was 12. Faced with a calculating degenerate killer, Jo has to use all his skills to lure him out into the open.