He and his girlfriend's best friend, Yuna Minagawa, were living together as roommates. They had planned a trip to attend an idol concert, but when Yuna fell ill and took to her bed, he stayed behind to nurse her back to health. Though flustered by her sweaty, heaving chest, he tried to remain calm—until she suddenly confessed, "I'm sorry... I faked being sick. I've always liked you, but I kept it hidden because you're my best friend's boyfriend." With that, she surprised him with a passionate kiss. Overwhelmed by shock, his self-control shattered completely, and he lost all reason, plunging recklessly into sex with her. Over the next three days, while his girlfriend was away, their affair intensified, deepening their forbidden bond. As she stripped, he was captivated by her fair, slender, yet shapely body, becoming ever more entranced by her irresistible allure.