Théo, 10 years old, is found dead in a vacant lot, his skull shattered. Théo was the treasured child of a lonely couple, Audrey and Paul Sander. Very quickly, Rovère's investigation turns towards a theory of family jealousy: Audrey's sister, Karine, had sent the couple letters with death threats. Karine, who lives with a young thug on parole, is therefore his first suspect. However, Nadia, who feels the couple are weighed down by a strange atmosphere, thinks that Rovère is on the wrong track.
