Captain Call's return to his Montana ranch sees him try to patch things up with his son Newt. Meanwhile Clara is attacked by the hired gunmen of a rival rancher and she must defend herself with her trusty six-shooter.
After returning the body of Gus McCrae to Lonesome Dove, Woodrow Call takes on the challenge of driving a herd of wild mustangs 2500 miles north to the Hat Creek Ranch in Montana. But tragedy, triumph, despair and deceit will greet him before he ever gets there.