While struggling to make friends after his parents’ divorce, Koyomi Takasaki meets Kazune Takigawa, but apparently, they already have. Kazune reveals that she’s from World Line 85, an alternate universe in which she and Koyomi are lovers. But in a reality where moving between dimensions is natural, could Koyomi be the one from another world?
If you still want to apologize, 
I'll hear it on the way home.
Wenn du dich immer noch entschuldigen willst,
tu das auf dem Weg nach Hause.
Но если хочешь извиниться —
выслушаю по дороге домой.