In the Season of the Sun — Kerry Newcomb

In 1829, four families left Virginia for St. Louis and a voyage up the Platte River to an open land of big sky. Guided by a half-breed frontiersman named Coyote Kilhenny, the pioneers did not know that they had reached the end of their journey in an ocean of swaying grass. In an act of horrific betrayal, Kilhenny sprang an ambush on the people who had trusted him most. When the carnage was over, two boys survived. Two brothers, swept apart in the orgy of violence. One would go with Kilhenny. The other would become the adopted son of a shaman of the Blackfeet tribe. And in lives lived on the wild frontier, they both know pleasure, pain, loss, and loyalty. And they would come to know each other once again-as warriors, as enemies, as brothers with a last chance for revenge...