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?
is it possible to go to, or return to, 
a particular parallel world?
Est-ce que c’est possible de choisir
le monde dans lequel on veut voyager ?
ma se io volessi tornare...
cioè, andare in un certo mondo parallelo,
а можно ли по своему желанию переместиться
или возвратиться в параллельный мир?