Grizzled insomniac San Francisco Homicide Inspector Clemson Yao enlists the help of Angie Strachan—a San Francisco realtor who once tried and failed to become the city's first female homicide inspector—to help him solve a series of frightening murders. The two face off against a ghoulish, black-humored serial killer who whimsically refers to his grotesque murders as "messies." Gripped by macabre obsession for a decade, he's evolved into a grandmaster of slow, anguished death, roaming the globe to catalog the most despicable and clever methods of execution. As Clem and Angie slowly unravel the murderer's clues, they realize he has his next victim already picked out—and it seems there is nothing they can do to stop him.