When a famous writer is found dead, the duo starts an investigation on the trail of a tragic fire that could be the source of a Machiavellian revenge.

A murderer interned in a psychiatric hospital is found dead in his room. The first clues seem to rule out the theory of an accident. Astrid and Raphaëlle embark on a difficult investigation. They are still unaware that this murder is the work of an organized gang operating from inside the hospital.