Jeun-Yung and his father participate in the biggest watermelon contest organized by his village. To make the trip easier, Jett brings the young boy a giant slide that crosses the valley, except that things get complicated when the watermelon rolls faster and faster without stopping. Will Jett, Jeun-Yung, Rocky and Donnie, who has been called in to help, be able to stop the watermelon and save the contest?