Led by their foreign female teacher, Suomi, the students of a certain high school set out on a trip to the Yarimoku nudist beach. There is only one rule the students must follow: it is forbidden to have erections. Hoping to create bonds between her students, Suomi pairs the female students with those who need to relieve their erections. Due to the visual spectacle provided by his classmates, Naotatsu Nagato is the first and only to break his teacher's rule. However, Naotatsu's seemingly insatiable lust proves to be problematic for his female classmates. [Written by MAL Rewrite]