Nobody Wants This

Fuutarou Uesugi is a poor, antisocial ace student who one day meets the rich transfer student Itsuki Nakano. They argue but when Uesugi realizes he is to be her tutor, he tries to get on better terms. While trying to do so he meets four other girls.

After a disastrous set-up by their families, two teens strike up a tentative friendship at their summer program - but deeper feelings aren't far behind.

In an alternate history where the male population is nearly decimated, eligible men serve as concubines to the woman shogun inside the walls of the Ooku.