In the sweltering summer countryside, siblings reunited after several years. Nobu was deeply interested in erotic things and proposed to Koji, 'Let me grope your sister's tits, so you can grope mine.' They immediately put it into action. Then Yuki said, 'Has everyone done H before? It feels really good, you know?' That single sentence became the trigger for them to have their first sex. And thus, the four teenagers came to know pleasure and spent their days having sex like monkeys whenever they got the chance.
