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?
and swap into a designated parallel world.
um mit sich selbst in einer
bestimmten anderen Welt zu tauschen.
e intercambiarse
con el yo de un mundo concreto.
e intercambiarse
con el yo de un mundo concreto.
pour s’envoyer
dans un monde spécifique.
che consente di scambiarsi di posto 
con il se stesso di un mondo parallelo designato.
por uma mudança paralela feita a
um mundo paralelo específico.
Он позволяет поменяться местами
с собой из конкретного мира.