Darius and his teams of atypical agents, the young and wealthy Duchesse, the experienced Marie-Jo and the former boxer Ben constitute the "Invisible" Brigade, a police taskforce specialized in cases with unidentified bodies. Every investigation is a race against the clock to discover not only what happened to the victims but mostly who they are.
Following Operation Fontana, the team was disbanded. Ben trains the police officers in the station's gym, Duchesse handles the menial tasks of Chistera's team, Marijo faces retirement and tries to manage Léa, her granddaughter. Darius has withdrawn to his country house, far from everything and everyone.
But when Chistera and Commander Risser, a newcomer to the Crime Squad, discover a small doll with traces of Darius's DNA on the body of an unidentified man, everything changes. Why does it bear his DNA? As victims with increasingly atypical identities are identified, the Invisibles team faces new personal challenges that will bring them closer than ever. As they piece together the stories of these Invisibles, they pull together. They are a team. And when a case directly affects their team leader and his mysterious, painful past, Duchess, Ben, and Marijo prove invaluable allies.