San Francisco homicide detective Kevin Russell has arrested serial rapists, murderers, and more sadistic thugs than he could remember. Nothing he has ever accomplished can prepare him for Conjesero, a supernatural serial killer who has been terrorizing the Americas for centuries. Conjesero—a creature with extraordinary intelligence and a vicious nature that has created a trail of bodies from Mexico to San Francisco—has always made law enforcement cower in fear and pretend that he doesn't exist. Only Kevin is willing to stand in its path. His desperation takes him on a journey inside the killer’s twisted world. There is nothing that he is unwilling to do, even if it means making a deal with the devil, to stop Conjesero or die trying.