Isolated from her tribe, Rhenna of the Free People walks alone, guarding the borderlands. But the mountain-dwelling shapeshifters, allies of her people, are disappearing, and word has come of a new evil. Known by their red stones and the chaos in their wake, the followers of the Stone God have made their ascent, spreading anger and war.

When the Stone God's priests capture a mountain dweller, Rhenna realizes she must help in the fight against an evil bent on controlling humanity's fate. Gathering together the enigmatic shaman Tahvo, the panther shapeshifter Cian and the rebel Quintus, she must unravel the pathways of the deities and bring down the most vicious god of all.