Harley Quinn is up to her usual tricks and infiltrated the Batcave, releasing a noxious gas that’s causing Batman to hallucinate — or is he? As his mortal enemies seem to break free of their monitors, the Dark Knight must fight to gain control and restore the safety and sanctity of his lair! But will the sinister forces of Mr. Freeze, Two-Face, Penguin, Bane, Joker, Poison Ivy and Scarecrow be more than he can withstand?