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?
At the same time, to each me who 
loved someone who wasn't Kazune:
Gleichzeitig
Y a todos los otros yos
que amaron a alguien que no eras tú.
Y a todos los otros yo
que amaron a alguien que no eras tú.
En même temps,
E allo stesso tempo,
Ao mesmo tempo, a cada um dos "eu" que
amam outra pessoa que não é a Kazune,
Опять же,