Shina, the secretary, is invited by the company president to serve as a private tutor for his only son at their home. The young, inexperienced playboy son eagerly anticipates meeting the attractive, single woman living alone. However, what awaits him is a trap orchestrated by his stepmother—one that leads him into Shina's dominant world of M training. The initial humiliation of the training sessions held before his stepmother gradually awakens his inner male masochist. As the sessions intensify, they draw in the stepmother's personal sex slave, escalating into a full-blown foursome. Deep within his psyche, the dormant seed of his masochism blossoms unmistakably through this experience.