Kyohei deeply loves his mother Fumie, who raised him all on her own. To express his daily gratitude, he constantly gives her gifts, which gradually blossom into romantic feelings. One day, Kyohei gifts Fumie a revealing, daring outfit. When she wears it, he is instantly aroused and they end up having sex. From then on, Kyohei continues giving her various erotic items, driving their forbidden relationship deeper into incestuous desire.