Kareki Tsunetaka, a veteran home security officer with 20 years of experience, currently guards his father's estate and its three new residents. These residents are Katsuragi Shouko, the voluptuous widow who has remarried Tsunetaka's father, and the children from her previous marriage – Sayaka, the attractive, big-breasted older sister and Yuki, the well-developed younger sister with an attitude. His intuition, honed from being a security officer, makes Tsunetaka realize that Shouko is planning to take over their household. He uses various surveillance devices to find out the three women's weaknesses and make recordings with which to blackmail them. Breasts that bounce heavily with every step, a well-developed ass that likens to a perfectly-ripened fruit, and indecent feelings for a young boy – She plays the part of a chaste wife, but the camera sees this bitch's true colors. Seizing onto Shouko's weakness, Tsunetaka lays waste to her chastity. As he fills her with sperm, the feeling of ecstasy reminds her of what it means to make love. The next target is... the mother, Katsuragi Shouko!!