Even after raising her children, Reiko maintains a good relationship with her husband. To her son, she's the enviable young mother praised by his friends. One day, the son catches Reiko and her husband in a passionate moment, stirring up lustful feelings. That night, while the father is out, the son confronts Reiko, confessing his arousal from witnessing their intimacy. Overwhelmed, Reiko tries to escape but is overpowered by her grown son. Despite her resistance, she's violated, and shockingly, finds herself responding to his advances...