""...all of the elements of a classic Vargas mystery are here." "
Jean-Baptiste Adamsberg has been appointed to Paris as a Commissaire in the police force of the 5th arrondissement. With a reputation for unorthodoxy, his preferred method of policing is to watch and wait. His colleagues, while amused at his distracted manner, are forced to admit that his methods are highly successful.
When strange blue chalk circles start appearing during the night on the city's pavements, Adamsberg is both intrigued and alarmed. He sees the circles as a portent of something more sinister and, to his colleagues amusement, insists in each circle being carefully photographed. When a woman is found in the blue circles with her throat cut Adamsberg is suddenly on the hunt for a killer whose obsession has turned to murder.