Two kids fall in love, then their parents fall in love, and suddenly they're about to become siblings. The only escape is a parallel universe, but every jump between worlds costs something they can't get back. This movie doesn't ask if they'll find a universe where they can be together, it asks what they're willing to lose to find out, and by the ending you'll understand why that question matters more than the answer.
Koyomi and Shiori's romance blooms at a research facility where their parents both work. Their connection deepens until fate intervenes: the two adults fall in love and decide to marry, which would make Koyomi and Shiori stepsiblings. Rather than accept this outcome, the couple makes an impossible choice. They plan to escape into a parallel universe where they can be together without the constraints of family law. Dimension-hopping exists as an established technology in their world, but the process carries hidden dangers that few understand. As Koyomi and Shiori begin their search across multiple realities, they confront an unsettling truth: finding a universe that will accept them might require sacrificing something fundamental about themselves or their relationship. Each jump pulls them further from their original timeline and closer to a point of no return. What begins as a desperate escape becomes an urgent question about whether love can survive the cost of chasing it across infinite worlds.