#1 New York Times bestselling author Kathy Reichs returns with a twisty, unputdownable thriller featuring forensic anthropologist Temperance Brennan, who finds herself enmeshed in a series of grisly animal killings that turn into something far more sinister. Small creatures--a rat, a rabbit, a squirrel--have been turning up throughout Charlotte, North Carolina, mutilated and displayed in the same bizarre manner. But one day, as Tempe is relaxing at home alongside her aimless, moody great-niece Tory, she's diverted by a disturbing call. Now, it seems, the perp is upping the ante. This find is larger. Could the remains be human? Tempe visits the scene and discovers that the victim is a dog. Someone's pet. As one who has always found animal cruelty deeply abhorrent, Tempe vows to help apprehend the person responsible for the killings, and due to Tory's especially layered knowledge of animal behavior, the young woman turns out to be a valuable ally in the hunt for answers.

Oddly, Tempe discovers that semi-retired homicide detective Erskine "Skinny" Slidell is equally outraged and committed. Needing a better understanding of possible motives, Tempe and Skinny seek input from a forensic psychologist. The doctor has no definitive answer but offers several possibilities, warning that the escalating pattern of aggression suggests even more macabre discoveries--and that the perp's focus may soon shift to humans. And then it happens. A woman is found disfigured and posed in a manner that mimics the earlier killings. As Tempe and Slidell follow the horrifying clues to a shocking conclusion, they're forced to confront an increasingly terrifying question: "What is pure evil?".