A Truth No One Knows.Everyone immediately gets to exterminating the monsters sent by Sakura, and after eliminating the first wave, the occult research society look over Kagari's theory with a copy Kotarou makes. Life is extinguished in most of them, but humans evolve in one of them, only for their civilization to be destroyed by the Key. Kotori tells the others that according to legend, the Key is looking for good memories...