In the remote forests of north Idaho, forest ranger Roy Farmer knows hardship intimately. Battling alcoholism and haunted by a tragic past he can't outrun, he stands atop a fire tower in the Bitterroot Wilderness, ready to end his life-until a violent summer storm sends a cartel plane crashing into the mountains around him.

Drawn reluctantly into the investigation, Roy discovers a cache of narcotics and a severed limb belonging to a missing pilot. The deeper he digs, the more he uncovers: a web of corruption in the nearby town of Lazarus, a brewing cartel war between a ruthless assassin and a violent biker gang, and a string of grisly murders that defy any human explanation.

As the bodies mount and the community fractures, Roy is forced to uphold a promise he made-and confront a malevolent entity that shows no remorse, no hesitation, and no fear.