Hiroshi, who is visiting his girlfriend's house, is captivated by her stepmother's beauty and her curves. That night, Hiroshi is kindly allowed to stay the night, and when he uses her bath, his stepmother washes his crotch, causing him to get an erection in the itchy air. Then, unable to fall asleep, he leaves the room in the middle of the night, and the soft curves of his stepmother, sleeping soundly in the bedroom, catch his eye...