Saddle tramp Sam MacKinnon is in trouble. Double-crossed by his partners after robbing a saloon and gambling hall, MacKinnon has been left behind in the mountains of southern New Mexico with busted ribs, a banged-up head, no gun, and no horse. Aging lawman Nelson Bookbinder and his Mescalero Apache scout, Nikita, are leading a small posse hot in pursuit of the bandits. Miraculously, MacKinnon escapes the law, finds his horse and rifle, and, despite his injuries, sets out on the vengeance trail.