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?

Pandora and Akubi are crossing dimensions to collect the "fragments of disaster," which have the power to destroy worlds. The first half of the film takes place in the setting of an American Western and the second half of the film takes place on a snowy mountain where mysterious spirits exist.