When her husband cancels at the last minute, Kana takes her adult son and his adult friend Yuji on a hot-spring trip. Her son passes out drunk, leaving Kana alone with Yuji in the family bath. Shocked by his thick erection but unable to hide her excitement, she eagerly sucks him. What begins as a casual encounter spirals out of control: no matter how many times he ejaculates, his youthful cock stays hard, pounding deep into her pussy and making her cum again and again until her body screams under his relentless rhythm.