The curator at Lyon's Fabric Museum is found murdered. Although the victim was undeniably professional, she was also tyrannical and manipulating with her staff and had plenty of enemies. On a more positive note, the museum's head of security is a childhood friend of Cherif.

With filming underway at the police station, the actor Tom Duval's assistant is found dead in a crime committed under the very noses of the police, on their premises. A real challenge for Cherif and Briard, who also face an internal investigation.