Gruelling winter gave way to bloody spring as Seamus Donegan and his fellow Army scouts rode west with the Kansas Pacific Railway. Led by the legendary Buffalo Bill Cody, they withstood blazing hit-and-run raids by Cheyenne Dog Soldiers - while trailed by a skulking enemy from Donegan's past. Then in midsummer, the fleeing Cheyenne camped. And the 5th Cavalry mounted the brutal surprise attack that would give rise to a fierce new warrier-leader named White Horse: the Battle of Summit Springs, 1869.