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?
the fact that we're born 
into a certain world,
dann können Sie am Ende sagen,
dass unsere Geburten,
alors notre naissance
dans un certain monde,
nós nasceremos em um certo mundo,
то и наше появление на свет,