An alien-spawned, mysterious mist blankets the northern half of Japan, transforming those who inhale it into ravenous, flesh-eating zombies hell-bent on devouring the surviving human population. Plunged into chaos, Japan is torn in two — the southern half of the country, where the populace remains untouched by the deadly gas, lives behind a heavily-fortified wall, while the northern half is a lawless, zombie-infected wasteland. Political forces are locked in a stalemate over whether the living dead should remain protected as family members or exterminated like a plague. The economy withers away, and all hope seems lost for the people and the nation of Japan. Hope arrives in the form of Kika (Yumiko Hara), a beautiful high school girl armed with a chainsaw sword powered by an artificial heart. Recruited by the government, Kika leads a ragtag group of desperados on a secret mission into the zombie-infected wilds to exterminate zombie queen Rikka and put an end to the plague of the living dead. But the road is fraught with a thriving zombie culture that, with its own designs on the living half of Japan, refuses to lay down and die.