After a long and bloody campaign against Chief War Heart's fierce tribe, Major Matt Devlin and his U.S. Dragoons have finally reached a truce. But the hard-won peace of the vast Dakota Territory is suddenly threatened when a vicious new enemy invades the wild prairie. With their Sharps .50-caliber rifles, Ned Wheatfall and his buffalo hunters stampede the reservation, killing bison and stirring up storm clouds of war. Now Devlin and his Dragoons have to move fast to stop the senseless slaughter and prevent a savage uprising that could once again turn the prairie land into hell on earth.