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…

Koyomi Hidaka and Shiori Sato meet at his father’s research center and begin to fall in love, but so do their parents, who eventually marry. To avoid becoming stepsiblings, they…