Rei Komatsu is 35 years old and lives with her husband and son. She overhears her son's phone conversation and feels intense jealousy toward the girl on the other end. Overcome by these emotions, she begins fantasizing about a sexual relationship with her son and indulges in masturbation. Her son accidentally discovers her in the act. One day, she sneaks into his room and finds him masturbating while having phone sex with the girl, before he even has a chance to open his porn magazine. Overcome by overwhelming desire and a burning heat throughout her body, Rei reaches out and touches her son. Though confused at first, he is drawn to his mother's mature allure, and their forbidden relationship gradually deepens.