Chenoa Winterhawk is a battle-hardened member of Oregon's elite U.S. Army Indian Scouts, sworn to protect travelers across treacherous mountain terrain and dark forests whispering of ancient terrors. As the daughter of legendary Civil War hero Chief Jolon Winterhawk, Chenoa is also a warrior bound by duty, struggling with injustices brought upon the Nez Perce amidst the broken promises that have forced another relocation of her tribe.

While escorting a military leader carrying a mining map of an underground river hidden deep inside the Blue Mountains, Chenoa is ambushed by a rogue Army unit in a deadly dirigible assault. Their sadistic leader is a traitor from her past, driven by revenge to destroy her family's legacy. The diabolical plan-destroy the mine and unleash the underground river, bringing a destructive flood onto sacred tribal lands to avenge personal betrayals.

Engaging ruthless military forces throughout unforgiving mountain wilderness and abandoned mines, Winterhawk wages the fiercest battle of her life. But she soon discovers that a much darker terror is also stalking her. Monstrous legends, roused from their ancient lair. These enormous creatures of myth were once faced by her father in an epic battle to the death. And now, it's her turn...