The hentai is based on the visual novel of the same name by The Triangle Game studio. In the depths of our planet lies the underground world of Roa, where magic and sorcery thrive. However, it is currently engulfed in a turf war between the Kingdom of Gloria and the forces of the Zeru Syndicate. Metzer, a young and well-respected officer in his own circles in Zeru's army, is ordered by his command to go on a sortie into the netherworld. He must make his way to Earth to seek out and gain the trust of the "Sweet Knights", who are female magicians from the Kingdom of Gloria. They are tasked with protecting sacred territory from encroachment by the Zeru Syndicate. Metzer eventually discovers the knights' weaknesses and decides to kidnap the girls and turn them into sex slaves.