Legend of The Shaman :

Legend of the Shaman is the third book in the Wyakin Trilogy. It continues with the tale of Cortez Modrables as he continues his life as shaman/healer to a non-treaty band of Nez Perce native Americans during their tragic conflicts with the U.S. Government over the lands of the Northwest in the 1870s. Cortez was intimately involved with the famed trek of the Nez Perce from Idaho Territory to British North America (Canada). Legend of the Shaman makes the story arc to the beginning of the Wyakin Trilogy portrayed in Legend of The Wyakin.