Miki accidentally overhears her son arguing with someone on the phone. Worried, she tries to approach him, but he seems reluctant to talk. After insisting that she's only concerned for her beloved son, he finally confesses that he couldn't perform during sex with her. Shocked by his words, Miki resolves to do something for him. The idea takes root—she will personally provide him with real sexual education using her own body. From then on, her son begins to develop a new interest in their relationship. He starts seeking her out regularly, gradually becoming addicted to their intimate encounters—but...