Toki no Hana -Chrono Alice-

Alice is a high schooler living in the "Showa" period, who meets a boy named Sho in the library, and the two instantly fall for each other. However, you find out that he's a high schooler from the "Reiwa" period. As "time" itself acts as a barrier for the two lovers, Alice also finds out that the library is struggling to stay open......