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?
Optional Shifting poses 
a variety of problems.
Optionalsprünge führen zu vielen Problemen.
Los optional shifts
suscitan varios problemas.
Los optional shifts
suscitan varios problemas.
Un tel transfert
présente plusieurs risques,
Gli spostamenti opzionali
 danno vita a non pochi problemi.
A mudança opcional abraça
vários tipos de problemas.