Rio is a 21-year-old university student living in Tokyo, attending a liberal arts college. She claims her club activity is tennis, but in reality, it's mostly lively drinking parties—your typical drinking circle. Every time, she gets swept up by her seniors, who routinely grope her F-cup breasts. She wakes up each morning to find senior members of the club sleeping beside her, with fragmented memories of the previous night's events lingering in her mind. So far, she's only had sex with two people, and she feels somewhat guilty toward her boyfriend. Yet, she may instinctively have a kinky personality. Today, she's hoping for sex that's so intensely pleasurable it'll leave a lasting impression.