Kouichi, the son, could no longer suppress his hidden desires for his stepmother, Anna. One day, he slips an aphrodisiac into her drink without her knowing. Unaware, Anna begins to feel her body heat up, overwhelmed by sudden pleasure, and retreats to her room where she indulges in masturbation. More sensitive than usual, she arches her body instinctively, climaxing with intense squirting—only to be discovered by Kouichi. Sensing his chance, Kouichi moves in on her. Unable to resist, Anna surrenders to his advances.