In a futuristic Tokyo, Katsumi Liqueur, a woman of Japanese descent born in the United States, travels to the city to visit her ailing mother, Fuyuka, who is hospitalized. While a taxi stalls in traffic, she takes a shortcut through an alley and stumbles upon a fierce battle between two policewomen and a monstrous creature. Recognizing the threat, the policewomen, chiefed by Rally Cheyenne, invite Katsumi to aid them. Although Katsumi has never met Cheyenne before, it becomes clear that Cheyenne has been expecting her arrival. Katsumi, skeptical of supernatural explanations, initially resists joining the fight, even though she remembers encountering this monster before.