It was every detective's nightmare. The worst-case scenario. A lead ignored or bungled, allowing something awful to be loose in the world. Something dark and evil, destroying life after life as it moved through the shadows. It was true that all detectives made mistakes and had to live with the regrets. But Bosch instinctively knew that this one was malignant. It would grow and grow inside until it darkened everything and he became the last victim, the last life destroyed.