As the perpetually lecherous Ataru and his friends prepare for a carnival at Tomobiki High School, they gradually realize the days are literally repeating themselves. Any effort to break the pattern dumps them back where they started. They later discover their town has been reduced to a circle of land a few miles across, poised on the back of a gigantic sea turtle--a reference to "Urushima Taro," a Japanese Rip Van Winkle story.
