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?
That he went to your world's past.
Er ist in die Vergangenheit
Ihrer Welt gereist.
Viajó al pasado de tu mundo.
Ha viajado al pasado de tu mundo.
Je sais qu’il est parti
dans le passé de votre monde.
So che in realtà è andato
 nel passato del vostro mondo.
Ele foi para o passado desse seu mundo.
Знаю, что он отправился
в прошлое вашего мира.