The turning point in Yuta's monotonous daily life came when he met a beautiful woman. Sayuki, who had arrived from the countryside, was a close friend of Yuta's mother—and he instantly fell head over heels for her charm. Desperate to get close to her and spend the night together, Yuta tried his best to build a connection, but his shyness and awkwardness kept him from joining any real conversation. As frustration and anxiety built up, Yuta impulsively began using her underwear as a masturbation aid. By what seemed like sheer coincidence, Sayuki appeared at the scene—but instead of getting angry, she kissed Yuta passionately. From that moment on, their relationship changed completely.