Charlie Pope, a recently released rapist/murderer from St. John's Security Hospital, has removed his electronic surveillance ankle bracelet and disappeared. Meanwhile, a woman and a man have been tortured and murdered in a manner that shares elements with the MOs of the Big Three, three serial killers currently incarcerated at St. John's. Investigator Lucas Davenport and his partner, Detective Sloan, initially finger Charlie as the murderer, but realize that he's not smart enough to have pulled off those crimes by himself. Are the Big Three secretly tutoring Charlie in advanced psychopathic techniques, or is the killer someone else entirely? This is the 16th police procedural in the Prey series.