The film was later split into two parts for Walt Disney's weekly television show, each part titled Ambush at Wagon Gap and White Man's Medicine.
A wagon train must find another way than fighting to cross hostile Pawnee territory in 19th Century America.
A small group of families join together to travel to Oregon in 1846. Their leader is ostensibly James Stephen (George Reeves, TV's Superman), who has made the trip before, and is now bringing his family along. John Grayson (Fess Parker), known as Doc for his ambition to study medicine, however, proves to be the real leader of the wagon train.
The pioneers deal with the elements and occasional raids, but after hostile Pawnees drive off their spare horses, they realize they may not make it to the Oregon Territory. While stopping at Fort Laramie, the pioneer children make friends with Sioux children. After the Sioux chief's son is injured in an accident, Doc Grayson helps heal him, earning the trust of the Sioux. As the story ends, the Sioux warriors escort the wagon train safely through Pawnee territory.
- Fess Parker as John 'Doc' Grayson
- Kathleen Crowley as Laura Thompson
- Jeff York as Hank Breckenridge
- David Stollery as Dan Thompson
- Sebastian Cabot as Bissonette
- George Reeves as James Stephen
- Doreen Tracey as Bobo Stephen
- Barbara Woodell as Mrs. Stephen
- John War Eagle as Wolf's Brother
- Cubby O'Brien as Jerry Stephen
- Tommy Cole as Jim Stephen
- Leslie Bradley as Spenser Armitage
- Morgan Woodward as Obie Foster
- Iron Eyes Cody as Many Stars
- Anthony Earl Numkena as Little Thunder
- Karen Pendleton as Myra Thompson
- Jane Liddell as Ruth Benjamin
- John Locke as Ed Benjamin
- Brand Stirling as Tom Foster (uncredited)
- Westward Ho, the Wagons! - lyrics by Tom Blackburn and music by George Bruns
- The Ballad of John Colter - lyrics by Tom Blackburn and music by George Bruns
- Wringle Wrangle - written by Stan Jones
- "I'm Lonely, My Darlin'" (based on Green Grow the Lilacs, Traditional) - lyrics by Fess Parker and music arrangement by George Bruns
- Pioneer's Prayer (from The Vanishing Prairie) - lyrics by Hazel "Gil" George and music by Paul J. Smith
- Props and setpieces from the film were utilized in creating the Indian Village attraction at Disneyland.