Oriane Verpilleux, Justine's court clerk, is found dead in a hallway. Tancelin starts the investigation despite her refusal to accept the substitute of Grégory, commandant Ludovic Marty. Furthermore, Justine insists on initiating the investigation against all advices, particularly these from procureur Élodie Roulier. Investigations reveal that Oriane had made a mistake in one of the procedures that led to the release of Yves Bazin, a dangerous robber.
