枯木常考 (Kareki Tsunetaka) has spent two decades as the ultimate “Jitaku Keibiin” — a home security guard who never leaves his room. Armed with hidden cameras, bugs, and powerful PC rigs, he watches every corner of the house.

His peaceful NEET life is shattered when his father remarries the cunning and seductive Kashiki Shoko. Shoko and her two daughters, the voluptuous eldest Sayaka and younger Yuki, plan to move into a new home in five days, taking the family fortune with them. Tsunetaka sees through their scheme: they’re after the house and inheritance.

To protect his sanctuary, he declares war on the three women. His first target is the big-breasted, obedient eldest daughter — Sayaka. Using secret recordings, threats, and relentless sexual training, he begins breaking her down, turning the proud young woman into his personal plaything.

Voyeurism, blackmail, mind-break, and intense creampie corruption await as the self-proclaimed Home Security Guard starts his mission to drive the invaders out — one orgasm at a time.