Appointed to conquer the “crime capital of the world,” the first police chief of Paris faces an epidemic of murder in the late 1600s. Assigned by Louis XIV, Nicolas de La Reynie begins by clearing the streets of filth and installing lanterns throughout Paris, turning it into the City of Light. The fearless La Reynie pursues criminals through the labyrinthine neighborhoods of the city. He unearths a tightly knit cabal of poisoners, witches, and renegade priests. Nobles settle scores by employing witches to craft poisons and by hiring priests to perform dark rituals in Paris’s most illustrious churches and cathedrals. As La Reynie continues his investigations, he is haunted by a single question: Could Louis’s mistresses could be involved in such nefarious plots? The pragmatic and principled La Reynie must decide just how far he will go to protect his king.