A brother who lost his close sister in a traffic accident has fond memories of her huge breasts that would bounce against him whenever they hugged. He can't forget the feeling or the lingering regret in his head and groin. One day, he discovers a service called "Sister Rental" online and decides to give it a try despite being warned about potential consequences if any lewd behavior occurs during the rental period, including immediate termination and house arrest. Will this desperate brother succeed in fulfilling his sexual fantasies through this underground option?

仲の良い妹を交通事故で失った過去を持つ兄。その妹が爆乳で、腕を組む度にムギュッと当たるオッパイぼよよんの感触が今でも忘れられなく、モヤモヤと心残りが頭と股間からずっと離れなかった… そんな或る日、ネットで見つけた「妹レンタル」に、早速、連絡をしてみるが、猥褻行為に至った場合は、その場でレンタル中止、そして出禁になると釘を刺されてしまう… そこで裏オプションにトライする兄、果たして成功するのか…