John Blaine (William Desmond) wins a contract to build a section of the Transcontinental Railroad. With his daughter Ann(Julie Bishop as Diane Duval) and his eighteen-year-old son, Noah (Noah Beery, Jr.), Blaine establishes his construction camp in the heart of Wyoming, on the border of hostile Indian territory.
Forces led by Rance Judd (Philo McCullough), Bart Eaton (Edmund Cobb)and the renegade Buckskin Joe (Frank Lackteen)unite to stop Blaine from completing the job on time. But with the leadership of construction engineer Tom Crosby (Onslow Stevens) and young Noah, the hardships of railroad pioneering are overcome.