The corpse of a mutilated woman is found along a road. For the Invisibles brigade, the relentlessness, the madness of the killer, are beyond doubt. While Duchess begins to have doubts about her ability to meet Ben on a daily basis, she crosses paths with the handsome Alexis, an old acquaintance... Darius confronts Chistera about Leïla, his adoptive sister. He understands that she is in serious danger, in a Crime case, with colossal stakes. At the same time, we discover two fiber installers, who go around the homes of Lille. If one is flirty and insistent with the women he meets, the other is more reserved, shy... What is the connection?