Lise and Clovis are enjoying their lives together with their son when an investigation into the violent deaths of two women leads them to realise that a serial killer is on the loose in Annecy.

The cause of the deaths becomes clear: the situation is critical.

Wagner and the healthcare team are helpless without a cure.

Darius Milanian has been dangerously busy but what is his aim?

Darius Milanian has been arrested, while Lise and Clovis face their worst nightmare.

Lise feels overwhelmed, but she and Clovis must make a final push to avert chaos.