Devastated by the death of a friend, Balthazar has left his job in Paris and spent the past six months sailing around the Atlantic, vowing never to touch a corpse again. His resolve is tested when he discovers a dead body near a remote island.

Balthazar is speeding away, trying to escape from the army that is pursuing him. Helene and a wounded man are with him in his car. But what could have possibly happened in the last 48 hours that brought them to this exact moment?

The badly beaten body of a woman is discovered in a chapel and the DNA sample that Balthazar analyzes links her death to that of two other women in the past 12 months. Were these women truly the victims of a serial killer?

Balthazar is investigating the case of a man and a woman who were found in the forest brutally murdered. However, soon he finds himself in a world between fantasy and reality that will help him realize a great deal about his life.

A bloody-faced little boy turns up at a gas station and disappears just as fast. Raphael and Bach are sent to locate him, but their investigation brings them face to face with some shocking revelations and a recent murder case.

The body of a missing man is found in a balloon-covered pool and the crime bears the marks of a psychopath who has been escaping from the police for a while now. Meanwhile, Raphael gets one step closer to the truth about Lise.

In the shocking finale of season 3, Janvier manages to escape just as Balthazar prepares to have the happiest day of his life. But after everything he has been through, does he even still have the right to believe in happiness?