To Every You I’ve Loved Before S01

In a world where traveling between parallel universes is a daily routine... Kouyumi Takasaki, who lives with his mother after his parents' divorce, attends a prep school. Kouyumi, due to the pressure of his studies and his antisocial nature, can't make friends. One day, he suddenly gets close to his classmate Kazune Takigawa, who tells him that he's from the 85th world, where they had a relationship together.