The kids stumble upon a hidden canyon filled with fruit trees. Chomper and Ruby think the fruit stinks! But the other kids like the fruit, and keep the place a secret so they can eat it all themselves. However, the secret doesn't seem like such a good idea when sharpteeth use the canyon to get into the Great Valley!

Ruby is convinced her story about the invisible Hidden Runner is made up. But that doesn't stop the other kids from having scary sleep stories. To make matters worse, Mr. Threehorn insists the Hidden Runner is real! With the help of Mr. Threehorn, the kids set out to face their fears.