Théo Luther est le plus redoutable chef de groupe de la Brigade Criminelle de Paris. Après avoir traqué un tueur d’enfants pendant de longs mois, il fait une dépression et met son mariage en péril.

Aujourd’hui, réintégré dans son unité, Théo est sous surveillance. Pour être pleinement réhabilité, il va devoir vaincre tant ses démons intimes que les criminels.

Sa première enquête le mène à Alice qu’il soupçonne du meurtre de ses parents. Incapable de prouver sa culpabilité, il enrage devant cette jeune femme qui le nargue ouvertement … Désormais, Luther combat les pires assassins du Grand Paris sous le regard d’une tueuse qui semble être - pourtant - la seule à le comprendre.

Morgane's efforts to improve her karma have finally paid off: Karadec turned out to be the father of her baby as she had hoped, and while she lost her home, he graciously agreed to take her in. For once, the universe seems to have good things in store for our heroine as this new season begins... But now that Morgane has gotten what she wanted, the question remains: can she make things last? Because while Morgane is gifted with chaos, insecurity, and adversity... She is much less so with happiness and simplicity. And just then... No sooner have Morgane and Karadec begun to find a balance in their new life as parents than it finds itself threatened by an irresistible attraction between them! But trying a romance when you're already co-parents, colleagues, and roommates... is it a genius idea? Or a great way to screw everything up?

Final season of HPI.