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 (Eihi Shiina) 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.