Told in his Cheyenne rites-of-passage vision (circa 1850) that his destiny is to leave his people and return with new wisdom, eager young Tumbling Hawk is captured by whites on his first war sortie, taken in by an Army officer sympathetic to the plight of the Indians, renamed ""Tom Hyde,"" schooled at Yale, and hired by the Bureau of Indian Affairs, where he has an affair of his own with the carnally adventuresome daughter of a powerful Washington politician. As Tumbling/Tom becomes more thoroughly enmeshed in the history-book backgrounds that flicker by (Civil War, the Kansas-Nebraska question, the battle over the route of the transcontinental railroad), his native consciousness is reraised, and he divines that his people are doomed unless they act quickly to save their lands and way of life: ""I abhor beyond words being the half-white redskinned rationalizer for the series of decisions which are rushing my people to captivity."" So, returning to his tribe with a stolen load of repeating rifles and tools to manufacture more, this self-styled Moses leads guerrilla actions against the war-weakened Army; message--the only way to defeat the white intruder is to fight (and ultimately become) like him. T.H.'s nobly tragic-ironic end--at the hands of his adoptive soldier father--is, like everything else here, passionately predictable, high-toned, and drawn out. But Seidman is to be commended for his precise, calmly cadenced narration and his careful panorama of the Cheyenne milieu--even if they don't quite manage to budge this well-intentioned sprawl from the inertia of its conventions.