"It's been five years already since we started this relationship." It was five years ago that I had an affair with Kitayama, my son's friend. After I found out that my husband had cheated on me for the third time, I was exhausted, and Kitayama comforted me with a gentle kiss, asking, "Is it okay if I'm not you?" I didn't want to disturb him while he was taking his entrance exams, but that night I made love to Kitayama. From that day on, we continued to meet up, hiding from my husband and son. As the days went by, I found myself becoming more and more dependent on Kitayama. Then, the day I found out that Kitayama had a new girlfriend, our relationship changed even more...