Kogami Kii and his fellow survivors have taken shelter in an abandoned shopping mall, narrowly escaping the murderous onslaught of the "magical girls" as they systematically destroy Tokyo. But is their sanctuary truly safe? Unbeknownst to the group, one of them is harboring a parasitic magical girl, hell-bent on accomplishing her mission of destruction. With nowhere left to run or hide, Kii and his companions must figure out a way to fight back against the magical menace!