Ryo, a young professor returning from research abroad, takes his pure-hearted, crybaby friend Akira to a decadent party, where things turn demonic.

Silene tracks down Amon, hoping to reawaken his demonic side. But in the ensuing battle, the human soul of Akira remains powerful.

Confronted by Akira, Ryo reveals the truth about demonkind and himself. Humans, demons and devilmen gather for an ultimate battle for the world.