#1 New York Times bestselling author Kathy Reichs returns with a twisty, magnetic "thriller of the highest order" (Bookreporter) featuring forensic anthropologist Temperance Brennan, who finds herself enmeshed in a series of grisly animal killings that escalate into something far more sinister.
Small creatures have been turning up throughout Charlotte, North Carolina, mutilated and displayed in a bizarre manner. But one day, as Tempe is relaxing at home alongside her aimless, moody great-niece Ruthie, she receives a disturbing report that a larger victim has turned up.

Tempe visits the crime scene and discovers that this time a dog has been sacrificed. Someone's pet. As one who has always found animal cruelty abhorrent, Tempe agrees to help apprehend the person responsible, and she acquires an equally outraged ally in semi-retired homicide detective Erskine "Skinny" Slidell. Needing a better understanding of possible motives, Tempe seeks input from a forensic psychologist, who warns that the escalating pattern of aggression suggests even more macabre discoveries—and a shift in the perp's focus to humans.

And then it happens. A woman is found disfigured and posed in a manner that mimics the animal killings. Subsequently, people Tempe cares about begin to go missing until it becomes clear she is being taunted, the target in a sick game that has her and Slidell racing against a ticking clock and asking a terrifying question: "What is pure evil?"