The first prince of the demon realm, Asus, does not follow the will of the demon king and lives a life of debauchery and is exiled to the human world. In order to return to the Demon Realm, Asus tries to regain the lost power by mixing his body with a human man, but he struggles because there is no man who can handle him. Just before he collapsed due to lack of magical power, Asth found Gaji-nam, who was returning home with a Bible.
Asth then begged him to treat him once because he thought he was about to die...