6Yukihime brings Tōta and Kurōmaru to UQ Holder HQ where they meet a whole team of immortals like them. As new recruits, they are shown a cold shoulder. To earn respect and become full-fledged members of UQ Holder, they must pass an initiation test. Without any warning, Tōta and Kurōmaru are dropped into a murky underground maze. Their mission: to escape from this dark monster-infested labyrinth within eight years. Tōta says he'll get out in a week. Can Tōta beat the odds?