A young farmer wishes to marry an Indian girl, but faces opposition on all sides. With other option, the old men tell him the story of his sister's capture by savages, a tale which takes him across the Medicine Line to a Nakoda village where buffalo are scarce and people are desperate. A Crow warrior and his captive white wife arrive seeking refuge. He promises much as he rides a Medicine Hat Horse that carries a Prophecy of Truth. Wishing to lead the Nakoda into victory, the Crow plans many battles. But when the infamous trader Tom Hardwick sets up a trading post, the Crow's strength is tested. The two are locked into a deadly battle that brings about the Sweet Grass Hills Massacre. But all is t as it seems. An ancient agreement must be kept, and although their lives are intertwined in their desperate struggle for power, the Medicine Hat Prophecy of Truth will t be defeated.