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?
Our study sessions became 
a great source of joy for me,
Ich habe mich zwar über
das gemeinsame Lernen gefreut,
Las sesiones de estudio
eran una alegría para mí,
Las sesiones de estudio
eran una alegría para mí,
Ces séances m’apportaient
beaucoup de bonheur.
Le sessioni di studio
 diventarono una vera e propria gioia per me,
A reunião de estudos foi um
grande prazer para mim,
Такие заняться стали моей
главной отдушиной,