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?
Then my grandfather explained 
the significance of possibilities to me,
Dann hat mir Großvater die Bedeutung
von Möglichkeiten erklärt.
Après ça,
E então, meu avô me explicou
o significado das possibilidades,
Потом дед рассказал мне,
как один выбор может изменить жизнь…