Minami Sayaka is a plain 30-year-old who has had no experience with men as a result of her one-sided love for childhood friend Sagisawa Ryosuke for 15 years. Even so she continues to refuse getting into a romance. Then one morning, when Sayaka wakes up, she sees a male stranger in front of her. She instantly panics but is told by the man who introduces himself as Machida Shohei, that they are dating and live together. It appears that Sayaka has completely no memories of the last three months. Furthermore, she has somehow transformed into a stylish person. Sayaka is shocked to learn that she has already slept with Machida and lost her virginity in this time. What happened in those three months? As Sayaka regains her lost memories, she begins to waver between the “wild, sweet” Sagisawa and “sadistic, normally cold but sometimes hot” Machida.