香織は年の離れたバツイチの雄一と数年前に結婚して雄一の連れ子・康太も含めた三人で暮らしている。毎日の暮らしに幸せを感じていた香織とは裏腹に母親ヅラする香織を康太は疎ましく思っていた。康太は香織を辱めようとこっそり利尿剤を飲ませアクシデントを装い自分も一緒に部屋に閉じ込もる。何も知らない香織は尿意が高まると腰をクネらせたり脚をクロスにして必死に耐えていたが我慢できず康太の前で失禁してしまう。小便で濡れた香織の姿に興奮した康太は香織に襲い掛かり汚れた股間を夢中で舐め続ける！！

Kaori married Yuichi, a divorced man much older than her, a few years ago, and the three of them live together, including Yuichi's son, Kota. While Kaori felt happy with her daily life, Kota resented her for acting like a mother. To humiliate Kaori, Kota secretly gave her a diuretic and then, staging an accident, locked himself in the room with her. Unaware of what had happened, Kaori desperately tried to hold it in, wriggling her hips and crossing her legs as her urge to urinate intensified, but she couldn't hold it any longer and wet herself in front of Kota. Excited by the sight of Kaori wet with urine, Kota pounced on her and frantically licked her soiled crotch!