On 11 August 1879, in the Dakota Territories, the Irish Fergus Coffey intends to propose his beloved Maryanne Stewart; however her family is attacked apparently by the Sioux and they vanish. Fergus joins to the experienced John Clay and William Parcher and a teenager to track down the family of settlers. Along their journey, the team-up with the army troop led by the sadistic and racist Captain Henry Victor that also believes that the Sioux are responsible for the abduction of the families in the territory. The quartet has friction with Henry and decides to ride without the escort of the army and the black cook Callaghan decides to travel with the group. After an Indian attack in the woods, the survivors discovers that the Sioux are not responsible for the slaughters but actually a pack of carnivorous creatures from underground called The Burrowers and they have to fight to survive.