There's this sexually-frustrated suburban housewife who gets raped by her hikkikimori neighbour (stereotypical obese bespactled nerd) and is blackmailed by him into continuing to having sex with him on regular basis, where he "trains" her into becoming a nymphomaniac. Unknown to both of them, her own daughter is spying on them having sex.
After the neighbour is unable to actually mindbreak the housewife into falling in love/lust with him after a period of time, he stops blackmailing her into having sex with him. The housewife then returns to her normal life, and she even has a revival of a honeymoon period with her husband due to her enhanced libido and sexual skills, but it doesn't last long, as he can only do 2 rounds at most every time they have sex.
The housewife, then becomes sexually frustrated again, and goes back to the house of the neighbour to hook up with him again, but she then sees her daughter's shoes left at the front door, implying that the daughter has already hooked up herself with the neighbour. The story ends with the housewife not knowing what should be her next course of action to take.