The Batman, after apprehending the Joker, escorts him back to Arkham Asylum. As he is processing the Joker, the Joker breaks free, takes over the Asylum, and causes a massive breakout. The Batman has to navigate the ghoulish Asylum, where he fights familiar villains as he tries to regain control from the Joker. But the Batman doesn't know that this was all planned to test how strong he is.
