Esther Lewanski is leaving the police, but on her last day becomes worried about Julia, a young mother who has disappeared, abandoning her baby Zoe. Despite the team's and Esther's efforts, Julia can't be found and, at the same time, a girl, Charlie, is found drowned. What's the connection between these two young women?

Commander Gabrielle Perez hunts for an 11-year-old boy who has vanished from hospital. Elouan had been admitted after developing an eating disorder, but was not yet well enough to leave the hospital. Gabrielle and assistant Alaoui learn that the family history is complicated, and they must investigate quickly, as Elouan's life is at risk.