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?
I take it you watched Grandpa 
go out instead of studying?
Du hast ohne zu lernen zugeschaut,
wie ich ausgehe?
Observaste cómo me iba
en vez de estudiar, ¿eh?
Has observado cómo me iba
en vez de estudiar, ¿eh?
Tu as bâclé tes révisions
pour m’espionner, je me trompe ?
Invece di studiare sei rimasta qui
 a vedere il nonno uscire di casa?
Em vez de estudar, você ficou
olhando o vovô sair, não?
А ты вместо уроков
сидела у окна и ждала меня?