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 this time, IP devices were just 
on the verge of practical realization,
Damals waren wir kurz vor
der Vollendung der IP-Terminals,
En aquella época estaban cerca
de completar los terminales IP,
En aquella época estaban a punto
de completar los terminales IP,
À cette époque,
In quel periodo erano a un passo
 dalla concretizzazione dell'interfaccia IP,
Naquela época,
Как раз в это время работа
над IP-терминалом подходила к концу.