Protagonist's daughter, Kanna, is highly praised for her excellent grades, athleticism, beauty and friendliness, but in reality she is a sloppy and disrespectful brat who constantly insults her own father and can't even clean up after herself. Protagonist plans to marry a young and kind busty teacher named Mei, who he hopes will help him improve his parenting skills and teach Kanna some manners. However, he soon discovers that his daughter has a bizarre fetish for wearing diapers and pleasuring herself, which he fears will ruin his chances with Mei. He decides to discipline Kanna harshly before their wedding.