Depressed from a broken heart, Naoto witnesses his mother Yuriko unable to hold it in and urinating in the garden. Excited by the sight of her peeing, Naoto makes Yuriko drink a strong diuretic tea and attacks her after she urinates. Although Yuriko resists, her body heats up contrary to her words, and a long-forgotten ache surges through her entire body, leading her to accept Naoto. Gradually, Yuriko begins to desire Naoto as well.