Judge Carole Massard is found dead in her office as she prepares to deliver her verdict in a criminal trial. Subsequently, the investigators go on the trail of a possible revenge by the accused. Morgane, for her part, is depressed. Weeks have passed since Ludo left her and, furthermore, she has discovered that Roxane, her worst enemy and Karadec's new girlfriend, is increasingly playing a leading role in the life of the brigade. Nothing is going well for the consultant who has to face an investigation that is much more complex than it seemed at first.

Roxane and the brigade are in charge of organizing Karadec's surprise birthday. It is a very complicated situation for Morgane who has just realized her feelings for the commander. At the same time, in his next research, Morgane does not find a body but an empty coffin. The missing body belongs to Hélène Lecoq, a notable place who lives in a mansion with her family.