Louisiana Sherriff’s Detective Dave Robicheaux and his longtime friend and partner Clete Purcel are vacationing in Montana’s spectacular Big Sky country when a series of suspicious events leads them to believe their lives—and the lives of their families—are in danger. In contrast to the tranquil beauty of Flathead Lake and the colorful summertime larch and fir unspooling across unblemished ranchland, a venomous presence lurks in the caves and hills, intent on destroying innocent lives. First, Alafair Robicheaux is nearly killed by an arrow while hiking alone on a trail. Then Clete’s daughter, Gretchen Horowitz, whom readers met in Burke’s previous bestseller Creole Belle, runs afoul of a local cop, with dire consequences.