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, the front entryway at 
my home opened twice in quick succession,
Auf der einen Seite öffnete sich die Vordertür
meines Hauses in kurzer Zeit zweimal
Por otro lado,
Por otro lado,
En peu de temps, j’ai dû rouvrir
deux fois la grande pièce de ma maison,
Nel frattempo,
Por outro lado, na minha casa, a porta da frente foi
aberta duas vezes por um curto período de tempo,
Ну а у меня за довольно короткое время
дважды открывались главные двери в дом.