Turtleshell Mountain is supposed to be the Most Joyous Place on Earth. That's what Tess Cameron is counting on when she invites all of her friends there for the weekend. Tess has a secret, a good secret, and she can't think of any better place to share it with the people she loves most. But Turtleshell Mountain has its own secrets. Something has awakened inside of the park. Something scarier than any ride. It won't be long before Tess and her friends are the only people left alive in Turtleshell Mountain… And that's when the nightmare will really begin.