Plagued by a series of frightening murders in San Francisco, Homicide Inspector Clemson Yao enlists the help of Angie Strachan, a realtor who tried—and failed—to become the city's first female homicide inspector. Facing off against a ghoulish serial killer who whimsically refers to his grotesque murders as "messies," Clem and Angie slowly unravel the murderer's clues, but their quarry is always one step ahead of them, and even an FBI profiler can't help them pin down the twisted mind behind the crimes. Gripped by a macabre obsession for a decade, the killer has evolved into a grandmaster of slow, anguished death, roaming the globe to catalog the most despicable methods of execution and keeping his research in dozens of leather-bound notebooks. It's a desperate race against time, for his next victims are already picked out, and it seems that no one can stop him.