Harka, the young Dakota, grows up as the companion of his exiled father. Both live as guests among the Blackfoot Indians. There, Harka witnesses the capture of a chief from his own tribe. For the first time in his life, he questions why Indians fight against Indians. Harka and Mattotaupa are torn from their refuge with the Blackfoots by the schemes of the adventurer and gold seeker Red Fox. They find themselves once again at the legendary cave in the Black Mountains, said to contain a treasure of gold and also regarded as the home of the ancestress of the Sons of the Great Bear.