Kasumi and her sister, Shizuku, were infected with the Medusa virus, which slowly eats away at the body. There is no cure, and Kasumi is selected to go into a cryogenically frozen state along with 159 others until a cure is found. In the undetermined future, Kasumi awakens to find herself and the others in an unfamiliar world with bloodthirsty monsters. Kasumi struggles to survive in a treacherous world in order to unlock its mysteries and learn the fate of her twin sister.
Written by Iwahara Yuji.