A series of experiments by a deranged scientist in search of immortality has left a chaotic and desolate world. In this post-apocalyptic future, the streets are filled with weapon-wielding zombies who are trained to form an undead army. Luckily for the few remaining human survivors, two sisters (Aya and Saki) travel Japan, killing as many of the undead as they can--but it seems like there is no end in sight for their fight. Are they destined to fight forever? A woman called Misery enlists their aid to destroy Himiko, the mistress of the undead. The two agree to aid Misery but instead find themselves in conflict with a group of human survivors being led by Aya's old friend Reiko. Tricked by Himiko, Saki sides with the zombie queen on the condition that her parents be resurrected. Now, Aya must fight alone and try to save her sister.