Sheriff Mary Beth Coupland (Coup) is called to Devil's Mountain to rescue a lost child. In the process she discovers a twelve-year-old skeleton and identifies the bones as Aletha, the wife of excommunicated Mennonite, Memmo Miller. Mixed in with the bones is one of only two gems known as the Tarpon Diamonds. Miller requested John Kole, Cherokee name, Fat Bear. Per Coup, Fat Bear is the most miserable son-of-a-bitch she has ever met.
Fat Bear's grandfather, the local Cherokee shaman, warns him about getting involved. He must obey his spirit animal. Reluctantly, Fat Bear takes the case to defend Miller and solve the mystery of the diamonds.
The deeper Fat Bear goes into investigation of Aletha's murder, the more evidence he finds indicating Miller is guilty. To complicate matters, he and Coup develop a fiery relationship which could affect the investigation.
As Coup and Fat Bear follow a trail of death, religious beliefs, ancient customs, and old mountain rituals, they must heed Grandfather's warning that Uktena, a dragon-like horned serpent, has transformed into human form and will destroy them both.
Piecing the evidence together, Coup and Fat Bear enter Devil's Cave to find the truth. But first, they must get past the Uktena.