It was a peaceful magical world thousands of years later. The Dark Lord had been defeated, people's lives had returned to normal, and children were learning and growing up happily at Hogwarts. But they didn't know that the first headmaster of Hogwarts was their night watch administrator, the head of the Slytherin family, who stood at the pinnacle of power on the European continent, was their librarian, and the daughter of Ravenclaw, one of the Four Giants, was actually the head of Sago's official forum. Things that had never been heard of by guys, memories and secrets from thousands of years ago were slowly unfolding. What was in front of them was a brand new world and future, and they encountered the legends of the unknown era.
The background is still the same, as a sequel a thousand years later, when the grandchildren are in school. The content is basically the story of two thousand-year-old bachelors showing off their affection without consciously, and hiding their merit and fame behind it.