Brothers and sisters reunite for the first time in several years in the midsummer countryside. Nobu is deeply interested in erotic things and makes a proposal to Koji. "I'll let you rub my sister's breasts, so let me rub your sister's breasts." Then, Yukino said, "Have you ever had sex? It's really good, isn't it?" And the four adolescents will know pleasure and will spend their days having sex like monkeys if they have a chance.
