Cassie Lockwood's mother died when she was little, so Cassie traveled with her father's Wild West show and became an amazingly skillful trick rider. When her father died, Cassie stayed with the show. Now she's discovered that "Uncle" Jason, the show's manager, has driven the show into debt and absconded with what little was left. Devastated, Cassie decides to try to find the hidden valley where her father had dreamed of putting down roots.