Mirei defied everyone's objections to raise Tatsuki as a single mother. Tatsuki grew up healthy and strong, graduating from college successfully, but instead of finding a full-time job, he continued working part-time while living at home. One night, Mirei woke up to the sensation of someone touching her body. Since then, Tatsuki's advances only escalated. Feeling that things had gone too far, Mirei decided to confront her son with a completely honest heart and planned an onsen trip together.