In 1878, two years after the Greasy Grass Fight that some called Custer's Last Stand, U.S. soldiers and government contractors rounded up 270 Arapaho people. From the very young to the very old, they were forced to walk from Fort Robinson in western Nebraska across half of what is now the state of Wyoming. Their destination: the Shoshone Indian Reservation. The new home of the Northern Arapaho was a wilderness, but it was theirs and they were glad. Then came a second and tragic event.

Within weeks, the Takers arrived to capture confused and terrified Indian children. The young were...