For fans of the Duke, this double feature features plenty of shoot `em up excitement. RIDERS OF DESTINY: John Wayne is a Secret Service agent sent on a mission to help ranchers whose water supply is threatened by a gang of crooks. THE SAGEBRUSH TRAIL: A young cowboy finds himself behind bars, wrongfully accused of a crime. One day, when his jailer is particularly careless, he sees his chance and escapes in order to clear his name.