The morning after a heavy snowfall, Yu Hirose was knocked down by an icy downhill car after staying up all night on his way home. When he wakes up, he is surprised to find that he has been reborn as a different person: an extremely good-looking boy with the same last name as him. Furthermore, the world has a unbalanced ratio of men and women, with women taking the lead role in society, and fewer men where it's natural for them to be protected. There are women who have too much sexual desire and want men, and men who are afraid of women and are on the defensive. Yuu's new school life begins in a world where chastity has been reversed.