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, likened by some to the famous Annie Oakley. When her father died, she continued to work with the show, having nowhere else to go.

Now Cassie has discovered that "Uncle" Jason, the show's manager, has driven the show into debt, and he's absconded with what little money was left. Devastated, Cassie decides to try to find the hidden valley where her father had dreamed of putting down...