Headstrong Thomas Dunson starts a thriving Texas cattle ranch with the help of his faithful trail hand, Groot, and his protégé, Matthew Garth, an orphan Dunson took under his wing when Matt was a boy. In need of money following the Civil War, Dunson and Matt lead a cattle drive to Missouri, where they will get a better price than locally, but the crotchety older man and his willful young partner begin to butt heads on the exhausting journey.