Two brothers running a successful ranch - Phil  (Benedict Cumberpatch), the man's manly one, and George (Jesse Plemons), known as Fatso to his brother - they drive their cattle to a rail town for sale and there George falls for Rose (Kirsten Dunst) who runs the hotel/restaurant aided by her willowy teenage son Peter (Kodi Smit-McPhee). George returns by motor car to court Rose and eventually they agree to marry and she and Peter move up to the ranch in the hills. Peter is made fun of by the cowboys but goes away to college. 

Phil dislikes Rose and terrorises her psycholgically - putting her in embarrassing situations - and drives her to drink. Peter returns during the vacation and sees what is going on. Despite Phil's initial antagonism gradually a relationship develops as Phil takes Peter under his wing and starts to make a cowboy of him.

Phil never wears gloves handling the raw hides that he makes ropes from, saying that he makes sure never to handle diseased animals (anthrax is aroound). Peter finds a dead cow in the wild and using his college knowledge (training to be a surgeon) be partially skins it and stashes the diseased hide in strips.

Phil cuts his hand moving a log pile with Peter, and Peter takes the opportunity to give Phil the rawhide strips he has for making him a rope. Sure enough soon Phil is weaving with the diseased rawhide using his hand with an open wound - inevitably he catches the disease and dies.

Thus Peter gets revenge for Phil's treatment of his mother, and Rose gets her life back with Geoge.