Kareki Tsunetaka views his stepmother and stepsisters as invaders of his home sanctuary and seeks a way to drive them out. He targets the impertinent younger sister, Yuki, by spying on her and discovering her insecurities. By recording her in a compromising moment and manipulating her with lies about a dubious breast enlargement drug, Tsunetaka blackmails Yuki into submission, initiating a coercive relationship to maintain control over his household.
Tsunetaka continues his "discipline" of the headstrong Yuki, eventually breaking her will and making her addicted to their sexual encounters. After a period of separation, Yuki returns to the house with a shocking revelation: she is pregnant with Tsunetaka's child. No longer the victim, a transformed and sexually aggressive Yuki now takes control, forcing the once-dominant Tsunetaka to take responsibility for his actions.
Seeking leverage to control the women in the house, Tsunetaka targets the seemingly perfect Sayaka. After failing to find any natural flaws in her behavior, he uses an aphrodisiac to induce a state of lust and records her in a compromising position. Using the footage as blackmail, Tsunetaka coerces the innocent student into a sexual encounter, ultimately securing her total submission through further recording and threats.
Tsunetaka continues to blackmail and manipulate Sayaka, forcing her into a state of total submission. Even after Sayaka returns months later pregnant with his child, Tsunetaka uses her vulnerability to further exploit her, eventually forcing her to embrace her role as his exclusive sex slave and welcoming her into his twisted "home guard" arrangement.