Just as Tōta and Kirië are about to make their way back from Kyoto, the Senkyōkan is attacked by none other than Tōta's younger sister, Cutlass! While Jinbei and Makabe manage to keep her attacks at bay, Cutlass soon reveals that the orbital elevator is the target of an impending nuclear missile attack--which claims the lives of over ten thousand civilians. Tōta, Kirië, and the rest of UQ HOLDER travel back in time in order to stop the attack from happening, but has their time already run out...?