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?
After all, they chose a world where 
they would absolutely never meet.
Denn sie haben eine Welt gewählt,
in der sie sich auf keinen Fall treffen.
Los dos eligieron un mundo
en el que no se conocerían.
Los dos eligieron un mundo
en el que no se conocerían.
Après tout, ils ont choisi un monde
où ils ne se rencontrent pas.
Anche perché loro due
Porque os dois escolheram um
mundo onde nunca se encontrariam.
В конце концов, они сами выбрали мир,
где никогда не пересекутся.