At the Galloping Grits Dude Ranch, Nancy and her friends hear a creepy story: Any horse that drinks from the lake under a full moon disappears. That night there's a full moon -- and the next day Nancy's pony, Star, vanishes!
Josh Fleckner is the biggest pest in the West, and he really wants a horse. Annie, the ranch manager's daughter, acts as if Star belongs to her. Now cowgirl Nancy is taking the reins, to corral the most beautiful Star in the West!