During her student days, Akari had a boyfriend with whom she had outstanding sexual chemistry. The chemistry was so intense that she could hardly think of anything else. Fearing she would lose herself in it, she made the decision to break up. However, now that she is an adult and on the verge of marriage with her fiancé, the memory of her ex-boyfriend remains deeply etched in her mind. Then, an invitation to a school reunion arrives. Fearing a reunion with her ex, she tried to notify them of her absence, but her fiancé arbitrarily decided she would attend. Forced to attend the reunion, the situation she feared became a reality. Upon reuniting with her ex, just a touch on her shoulder brings back memories of the days when she was driven crazy by sex. Swept away by the impulse, she tells herself, "Just once..." and goes to a hotel, but she completely forgets about the fiancé waiting at home and drowns in sex with her ex, who knows every single one of her erogenous zones.