Fifteen-year-old Will Braddock works as a hunter for his uncle's survey team, as the transcontinental railroad extends across Wyoming in 1868. Paddy O'Hannigan is determined to get even with those who caused the death of his father—which means Will, his uncle, and former slave Homer Garcon. And Paddy has other nefarious designs: he intends to blow up presidential candidate Ulysses S.Grant's train on the general's campaign trip into Wyoming. After saving a German count from a bear attack, in which he himself is badly mauled, Will must immediately turn his attention to his human opponent, the deadly and ruthless Paddy O'Hannigan.