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?
From her frame of reference, 
Ryou and I weren't 0.
Von ihr aus gesehen sind Ryo
und ich nicht auf null.
Para ella, Ryo y yo
tampoco somos del mundo cero.
Para ella, Ryo y yo
tampoco somos del mundo cero.
De son point de vue aussi,
nous ne sommes plus les mêmes.
Dal suo punto di vista, però,
 né io né Ryo siamo lo zero.
Do ponto de vista dessa pessoa,
Да и для неё самой…
мы с Рё уже не «нулевые».