Isamina, who was supposed to be just an ordinary village girl, suddenly finds the mark of a saint appearing on her hand one day. She was supposed to summon an angel to become a saint, but by mistake, she summoned a beautiful demon, Vermillion! If this were found out by the kingdom, both the village and Isamina herself would be in danger. Therefore, she decides to pretend that the summoned demon is an angel. However, as the demon’s meal, she must offer up her own body――!?