"The Dark Knight investigates below the old ruins of Arkham Asylum, uncovering a demon-infested mystery tying Gotham to the Orgham family from centuries back...including the existence of Batman! With Nightwing and Batgirl helping along the way, Batman struggles to fight off an Azmer demon's hold on his mind, and the only thing in its way are Bruce's own inner demons...and Barbatos."--Publisher.