Four women share a determination to stop a killer who has been stalking newlyweds in San Francisco. Each of the four friends holds a piece of the puzzle: Lindsay Boxer is a homicide inspector in the San Francisco Police Department, Claire Washburn is a medical examiner, Jill Bernhardt is an assistant DA, and Cindy Thomas just started working the crime desk of the San Francisco Chronicle . But the usual procedures aren't bringing them any closer to stopping the killings. So these resolute women form a group dubbed the Women's Murder Club to collaborate outside the box, pursuing the case by sidestepping their bosses and giving one another a hand. The four women develop intense bonds as they track a killer whose crimes have stunned an entire city. It is a killer who thinks, What is the worst thing anyone has ever done?-and then goes far beyond it. Working together, the Women's Murder Club hunts down this most terrifying and unexpected killer before a shocking conclusion in which everything they knew turns out to be devastatingly wrong.