Tokuma Nishioka

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?

Koyomi Hidaka is a boy in elementary school who lives with his father after his parents' divorce. One day, he meets a girl named Shiori Sato at his father's workplace. The two of them begin to fall in love, but then they learn that their parents are going to marry each other, so they decide to run away to a parallel world in which they aren't destined to become brother and sister.