Summer has descended upon Cromartie High, and the students are lining up to take off their clothes...to join the school sumo club! Masked Takenouchi becomes the club's rising star, and the Four Great Ones (all five of them!) find themselves impromptu goodwill ambassadors, explaining the finer points of loincloths to a series of foreign guests. Despite the teaser text, no one's doing anything dirty! Except for Hayashida, who's having an affair with a married woman. Again.