The railroad tycoons hear about the wagon train and decide to stop it. They think if word gets out it will give the West a bad name. The hire a gunslinger named Slade to stop the wagon train. He tried several times to sabotage the train and failed miserably. He gets shot and killed in a gunfight with Julien the bookseller.
Harlo leads the settlers into Sioux Indian Territory, and they accidentally camped on a reservation. The Indians decided to escort them because they are so glad the settlers are leaving.
Some of the settlers realize Harlo was the wagon master on the fatal Donner trip. These settlers got stranded in a snowstorm with no food, and they all died except Harlo. When the men confront Harlo, he rides off leaving the settlers to fend for themselves.
The railroad has sent the Calvary to kill the settlers. The leader is the same man who stole all the food and caused the Donner trip disaster. He is Harlo's arch enemy. When the soldiers see that the wagon train is full of women, children and failed settlers, they refuse to fire. Harlo comes back to face his enemy.
This was the last movie John Candy made. He died in his sleep just before they finished the film.