Renée Ballard and the LAPD's Open-Unsolved Unit find a DNA connection between a recently arrested man, and a serial rapist and murderer who went quiet twenty years ago. The detainee's father was the Pillowcase Rapist, responsible for a five-year reign of terror. However, when they move in on their suspect, they encounter a baffling web of secrets. Ballard's badge, gun, and ID are stolen - a theft she can't report without giving her enemies in the department the ammunition they need to end her career. She has no choice but to go outside the department for help, which leads her to the door of Harry Bosch. Meanwhile, Bosch's daughter Maddie wants to supplement her work as a patrol officer by investigating cold cases with Ballard. But Renée soon learns that Maddie has an ulterior motive for getting access to the city's library of lost souls.