A trail drive is coming to an end, and the payoff for the aging hands leaves the three punchers looking for a way to dodge the coming winter: Blue, [Lee Majors], Dutchy, [Anthony Zerbe], and Will Penny, [Charlton Heston]. They decide to drift south, hoping for a fresh start, and a young cowboy’s desire to visit his dying father hints there might be work at the Flat Iron ranch.
One morning Blue is about to fire at a bull elk along a river bottom, but the elk is shot by an unseen shooter. As Blue and Dutchy press in to claim the meat, they run into the shooter—a rawhider—and his family. The two groups clash over the elk, gunfire erupts, and Will arrives to a brutal scene: he shoots and kills one of the rawhider’s sons. The rawhider swears biblical revenge. Dutchy accidentally wounds himself in the melee, so the trio heads off to find a doctor. They stop at a nearby trail store where they meet Catherine Allen, [Joan Hackett], and her son Horace, [Jon Gries], share a few drinks, and then move on to the nearest town, leaving Dutchy with the doctor. Blue heads to town to look for work, while Will continues alone. He discovers a riderless horse and a dead cowboy, and he returns the body to the Flat Iron ranch, where he’s offered a job.
Will hires on to patrol the distant boundaries of the Flat Iron ranch over the winter. At the upper range, he finds Catherine and Horace staying in the line-rider’s cabin after their guide abandons them. He rides away to inspect the fence line, warning them they must be gone when he returns in a week.
The next morning, while Will sleeps outside near the fence, the rawhider group ambushes him, beating him severely and knifing him. They rob him and leave him for dead, but he somehow drags himself to the cabin, where Catherine slowly nurses him back to health. As the winter drags on, Will and Catherine fall in love, and he develops a fatherly tenderness toward Horace.
As Christmas approaches, the Quint family bursts into the cabin—Rafe Quint, [Bruce Dern]—and forces Will to shoulder chores while Catherine is pressed to choose among one of the hot-tempered, ready-to-brawl Quint sons. After several tense days, Catherine distracts the two Quint brothers so Will can slip away. At the same time, Blue and Dutchy, his old trail partners, arrive in search of him. Will and Blue return to the cabin and mount a bold stand to free Catherine and Horace, using a bag of sulfur in the chimney to smoke out the rawhiders and then shooting them all.
With the rawhiders dead, the Flat Iron trail boss arrives, and Will comes to a hard realization: he’s too old and set in his ways to settle into a quiet domestic life with Catherine. Despite her protests, he leaves behind the life he’s known. Grasping the weight of what he’s giving up, he rides away with Dutchy and Blue to honor a bet with the store owner and continue life as a trail hand, donating his wages from the ranch to Catherine.
