North-West Mounted Police Sub-Inspector O'Rourke and his Cree half brother Cajou are returning from a trapping trip in northern Canada when they encounter a burned wagon train and sole survivor Grace. Despite the advice of the Métis people (Canada) scout Batouche the naive new Mountie commander Inspector Benton (recently arrived from England) believes it to be a Cree attack, however the Sioux from across the border are trying to force the Cree into being allies in their struggle with the U.S. 7th Cavalry Regiment (United States).