On the outskirts of Paris, two men have been found with their throats cut. In Normandy, two stags have been killed and their hearts cut out. Meanwhile a seventy-five-year-old nurse who has murdered several of her patients has escaped from prison. Is there a connection between the three cases?

In this mystery, Commissaire Adamsberg is pitted against nemeses past and present: Ariane Lagarde, France's foremost pathologist and Adamsberg's enemy since they argued over a case twenty-three years earlier, and Louis Veyrenc, a new recruit with a grudge, who has been assigned the job of protecting the Commissaire's ex-girlfriend. As the different strands of Vargas's compelling story begin to intertwine, events move towards a gripping climax...