Huge Tiki heads with a grudge against Grover's Mill are turning the town back into a jungle—it's the Weird Zone's weirdest trouble yet! All Mike and his friends want to do is play a game of baseball on their first day of summer vacation. But when Liz gets up to bat, home plate begins to shake. Suddenly, five odd-looking men carrying long sticks appear in the middle of the field. When they bang their sticks on the ground, Grover's Mill turns into a jungle, and giant Tiki heads start popping out of the earth. Even worse, these evil Tiki heads are out for revenge against Grover's Mill! An ancient prophecy predicts that the Tiki heads will destroy Grover's Mill. The kids must find a way to prevent it from coming true—and then turn back time. But the Tiki heads seem too powerful to beat. Can the kids save the day before they get trapped in the past?