After returning home to Tokyo after a long absence, Takashi was excited to see his sister Mary again. He couldn't believe how sexy she had become since he last saw her. Innocent and naive, Mary didn't seem to understand that her lack of a boyfriend in Tokyo made her an easy target for Takashi's advances. When he heard that she would go back to being a virgin if they didn't have sex for a while, he knew he had to take advantage of the situation.

久しぶりに東京から実家に帰ってきたメアリーを出迎えた弟のタカシは久しぶりに会った姉がエロい身体になっていて興奮してしまう。少し天然で純朴で人を疑うことを知らない姉は、東京ではずっと彼氏が出来なかったらしく、そんな性格に付け込んで「しばらくセックスしないとセカンドバージンと言って処女に戻る」と嘘をつく。※ 配信方法によって収録内容が異なる場合があります。