Unaware that the Civil War has ended, Col. John Henry Thomas (John Wayne) successfully attacks a Confederate company led by James Langdon (Rock Hudson). With the remnants of Langdon's squadron fleeing to Mexico, Thomas and his adopted Native American son, Blue Boy (Roman Gabriel), gather a herd of horses and head for the border with their company, to sell them. After Langdon's caravan is captured by a Mexican general (Tony Aguilar), Thomas nobly sacrifices the horses to free them.
