The story takes place in the world where both science and magic has advanced. Arkham City is a metropolises prospered by highly advanced magic. However it is threatened by a criminal syndicate Black Lodge. They set the Master Telion, who is the greatest wizard as well as the worst criminal, up as the leader, and they give free reign to their desire to rampage the city. Hado Family Group, the guardian of the city, makes a robot to beat Black Lodge. It is Demonbane.
Now, the battle between Demonbane and Mater Telion's Black Lodge starts