A group of Sioux come to shelter in Canada from the Indian wars in the United States following Custer's last stand at the Battle of the Little Bighorn. They are given permission to remain by the Canadian government represented by three Mounties. Caucasian Indian-fighters from Montana searching for 40 stolen horses discover the Sioux settlement and mistakenly assume their horses are theirs. In the white men's surprise attack they murder many Indians, steal many horses, and kidnap an integrated white young woman recognized as having been kidnapped in a raid years earlier. The Mounties promise justice, track, capture, and begin the week-long ride to a trial at court. During the week tables turn back and forth, backstories shared, some discussion about American gun culture and violence, and the woman is killed. Eventually the Caucasian Americans are lured to what may be their lost horses but a stampede erupts and the Sioux manage drive the white men over the cliff like buffalos to their death. Without a shot fired and the deal maintained the Sioux remain in Canada while the Mounties return to their fort where the senior will finally retire. In response the North-West Mounted Police are formed, the forerunner to the Royal Canadian Mounted Police.
The film was the directorial debut of Burt Kennedy, who had established himself by the late 1950s as one of the leading writers of Westerns. It was originally called Royal Canadian Mounted. Kennedy later recalled, "I didn't know what I was doing. I remember the first shot had like 400 horses in it, and I got the shot and the cameraman said, 'What do we do now?' And I thought, 'You mean I gotta do more?' So that's the reason I went into television to find out how you shoot pictures." He also said "I had a wonderful cameraman... it was beautiful country... the story was pretty good actually, because it was based on an actual event, but - I was so used to playing scenes in Randy pictures, I thought I could get away with them. But I couldn't. You can play good scenes with bad actors and bad scenes. So I trapped myself... like he didn't know what he was doing. It wasn't his fault. He was so grim in it. And the picture was so grim."
