Diamonds are being smuggled across the border from Mexico in a specially made shoe of a palomino mare. One of the smugglers is killed when the mare runs off. The sheriff blames Trigger for the death. To keep his horse from being destroyed, Roy confesses and goes to jail. The smugglers buy Trigger and put him to work smuggling diamonds. The mare, who had earlier heard a trist with Trigger, foals Trigger, Jr. who Roy, finally out of jail, uses to help capture the smugglers.
as Roy Rogers
as Trigger - Roy's Horse
as Stormy Billings
as Pepé Valdez
as Sparrow Biffle
as Jeff Middleton, Owner of Oro City Hotel
as Oro City Sheriff
as Henchman Ben
as Henchman Ed Hart
as Bartender Spud
as Guard
as Old Man
as Foy