When his aunt Sayuri suddenly came to Tokyo from the countryside and decided to stay at his apartment, Toshiki, the nephew, began cleaning the room in a hurry. Before he finished cleaning, the doorbell rang and Sayuri arrived. Toshiki was surprised at Sayuri's youthful appearance, whom he hadn't seen in a long time. "For the next three days, I'll be alone with my beautiful aunt in this small apartment..." While he was thinking this, Toshiki's lower body started to go out of control, going against reason...