Antoine Verlaque doesn't like Christmas. The decorations appear in the shops far too early and festive tourists swarm the streets. But his wife and partner Marine Bonnet is determined to make this a Christmas they can both enjoy, beginning with the carol sing at the Cathedral Saint Sauveur, a beautiful service in a packed church. When a man is poisoned at the service, the list of suspects almost fills the church itself, from the visiting vendors at the Christmas fair to the victim's unhappy wife and his disgruntled business partner.