Police Chief Herville is found dead in a Chinese restaurant in the 13th arrondissement of Paris. Gilou must break the news to Laure, who is being treated in a police rehabilitation centre. Now in charge of the unit, Gilou begins investigating with new recruit Ali, who is fresh out of training.

Meanwhile, Judge Roban returns to work from his time off sick only to find he is soon due to take compulsory retirement. And lawyer Joséphine struggles to adapt to life in prison while awaiting trial.