To settle an ancient rivalry between Heaven and the Demon Realm, a human named Yamato is chosen as the impartial judge. Filica, the haughty daughter of the Great Demon Lord, attempts to secure his loyalty through a seductive contract, only to find herself in a fierce competition with Sera, a representative from the celestial realm. As Filica uses her charms to bind Yamato to her, the battle for the human's favor escalates into a chaotic struggle of pleasure and power.
Yamato finds himself caught in an escalating pleasure battle between the demon Filica and the angel Sera. After a risky encounter on a train, Sera begins to develop genuine feelings for Yamato, leading to a fierce competition as both supernatural women vie for his affection and loyalty. As the tension peaks, Yamato is pressured to make a final decision between the angel and the demon.