One day, Shihori returned home drenched in the rain. Her son, Yuuichi, could no longer suppress his racing heartbeat as he watched water droplets cling to her clothes, tightly pressed against her body. As he headed to his room to change, he encountered his mother on the way to fetch a towel—her nipples clearly hardened. From that moment on, Yuuichi found himself increasingly drawn to Shihori, and eventually came upon her sleeping defenselessly. Overwhelmed by uncontrollable desire, he repeatedly reached out and touched his mother's nipples.