A woman who was formerly a company president's secretary remarries a man who runs a business. Worried about her stepson, who remains shut-in at home even after reaching adulthood, she kindly continues to care for him as a devoted stepmother. One day, she enters his room to encourage him, only to realize her underwear has mysteriously disappeared. Seeing her son frantically apologizing, she feels troubled but gently forgives him, embracing him with compassion. However, she is suddenly overpowered by his intense arousal, pinned down, and pushed to the brink of penetration...!