A series of demonic invasions has landed upon the Gracio Empire, plunging the human empire into chaos as the demonic forces attack without warning. As the one who sealed away its leader in the past, the Holy Knight Luviria realizes that this is the foreboding sign for the resurrection of the demon lord, leader of the demonic forces. Determined to stop the demon lord before he returns to full strength, Luviria sets out with a brigade of knights to bring down the demonic leader, striking deep into the demonic domain.
Unbeknownst to her, however, the newly resurrected demon lord, besides being a ruthless and deviant soul, has also taken a special interest in her. With the help of his equally-twisted sister and his witch subordinate, he comes up with a devious plan to corrupt the righteous knight…