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. And no chance because 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. But fate has something else in mind for Sam MacKinnon.