Akari had a boyfriend in her student days with whom she had incredible sexual chemistry. Their sexual compatibility was so good that she couldn't think about anything else. She broke up with him because she knew things couldn't continue like this, but even now, as she is about to marry her fiancé whom she met after becoming a working adult, her ex-boyfriend remains deeply etched in her memory. Then, she receives an invitation to a class reunion. Fearing she might run into her ex-boyfriend again, she tries to decline the invitation, but her fiancé signs in and registers her attendance without her knowledge. Left with no choice, she attends the reunion, and her worst fears come true. Reuniting with her ex-boyfriend, just his touch on the shoulder brings back memories of that day when she was driven wild by sex. Swept away by the surging urges, she thinks, "Just this once..." and goes to a hotel, but forgetting about her fiancé waiting at home, she becomes addicted to sex with her ex-boyfriend, who knows her erogenous zones intimately.