Detective Dave Robicheaux travels to the mountains of Montana to help his best friend and unearths a larger plot that threatens them both. Oil speculator Weldon Sonnier is the patriarch of a troubled family intimately bound to the CIA, the Mob, and the Klan. Now, the murder of a cop and a bizarre assassination attempt pull Detective Dave Robicheaux into the Sonniers' hellish world of madness, murder, and incest. But Robicheaux has devils of his own--and they may just destroy the tormented investigator and the two people he holds most dear.