Wife Ayumi suffers from a sexless marriage and copes by masturbating daily, yet her emotional loneliness remains unresolved. One day, she accidentally sees her stepson's erect penis and impulsively says, "Should I help you jerk off?" From that moment, their relationship begins down a forbidden path. Drawn to his youthful, vibrant body so different from her husband's, Ayumi grows increasingly attracted to him. Soon, she becomes addicted to the pleasure of feeling his creampie, his semen filling her deep inside. As new emotions awaken, her bond with him grows ever deeper.