Turning the powerful hypnotism capabilities of his penlight on his foster mother and stepsisters, Mamiya Yuuichi uses his family as an outlet for his sexual desires. As the absurdity that is the Mamiya household unfurls, the neighbors begin to notice. Worrying for the moral state of the Mamiya household, their neighbor Nanae comes over to talk. She is powerless to resist his powers of hypnotism, and their other neighbor, Yachiyo, later shares the same fate. Finally Ruiko, President of the Neighborhood Association, approaches the Mamiyas’ house…

Our protagonist, Takesaka Munetaka, fails the first time he tries having sex with his lover due to trauma he experienced in the past. His sister Ritsuka and his cousin Momotani Mashiro literally put their bodies on the line to give him “sex lessons” and help him recover from his trauma. However, his other sister, Wakana, who gave him his trauma in the first place, joins the fray and the lessons become more than just lessons! Here begins the sisters’ war over their little brother!!