Beyond the boundaries of our ordinary existence lies a dreadful parallel world where demons dwell and humans dare not tread. For centuries, peace has existed between our world and theirs. To preserve that fragile balance and to ensure the survival of humankind, a new deal must be brokered, but dark and powerful forces lust to destroy the accord. When a militant group rises from the shadows, two elite agents are mobilized to counter the destructive forces and preserve the balance of our universe.
(Source: Sentai Filmworks)
— Description from AniList community (anilist.co).
