Above the Cours Mirabeau in Aix, Christmas lights sparkle. However, a sense of tranquility does not settle in, as murder knows no holidays. Passersby in the festively decorated old town of Aix en Provence freeze in horror: a Santa Claus, the well-known Père Noël of the city, lies dead in the window of a large store – shot. Commissioner Papperin and his homicide team are completely in the dark: Who is the victim? What is the motive? And: Who is the murderer? Clues lead them to the research laboratories of the University of Aix-Marseille, to the Islamist scene, to the world of big business, and to the lonely winter landscape along the rugged coastline between Cassis and Marseille.