Nagara and friends use his power to survey new worlds in an effort to get back home. Meanwhile, the others students discuss the bombshell from Ms. Aki that some students were able to use their powers beforehand, and that may be what set them adrift.

Having learned the truth about This World, groups led by Ms. Aki and Hoshi prepare to go their separate ways. Nagara finds himself in an upside-down world he cannot freely leave, and is forced to work on building a Tower of Babel that reaches downward.

In a vast frozen waste, twins Sou and Seiji have been fighting each other for millennia. Ms. Aki says that to change the world, they need the twins' "Reverse" power, and Nagara and Mizuho come to assist. Yamabiko questions Sakura, one of Mizuho's cats.