The Flaming Frontier (1926)

Bob Langdon a young Pony Express rider is given an appointment to West Point but is forced to leave the academy as the result of political intrigue stirred up by enemies of his friend General George A Custer Bob returns to the west and is made a scout for Custers 7th Cavalry At the Battle of Little Big Horn Custer sends Bob with a message for aid and Bob becomes the only survivor of the battle