In 1885 a large band of half-breed Canadian rebels known as Metis, slip south over the border into Montana Territory. They carry with them a stolen Gatling gun and a strong desire to benefit, by any means, from the USA's wealth. Tough and experienced Deputy United States Marshal Jesse Bronson, is sent out to apprehend them. He is accompanied by a corporal of the Canadian Northwest Mounted Police. Bronson at first deeply resents the enforced presence of the red-coated Mountie and it is only after surviving numerous violent encounters that they finally begin to form a genuine bond. The fast moving tale encompasses a bloody confrontation in the gold mining camp of Alder Gulch, followed by a pursuit down the swollen Missouri River on log rafts and then onto a final momentous showdown in the town of Great Falls.