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?
You're going to experience 
all sorts of things.
Du wirst von jetzt an viele Dinge erleben.
Experimentarás muchas cosas, Koyomi.
Experimentarás muchas cosas, Koyomi.
Tu vas expérimenter
tant de choses en grandissant…
Farai un sacco di esperienze, da qui in avanti.
De agora em diante, você vai
passar por muitas experiências.
Впереди тебя ждёт насыщенная жизнь!