The Joker attacks Gotham 's Mayor's Office , but is defeated by Batman who takes him to Arkham Asylum . Due to a recent fire at Blackgate Prison, a large number of prisoners in perfect mental condition have been temporarily relocated to Arkham, many of whom are in the Joker's gang. As Batman escorts the guards taking the Joker inside, Arkham security is taken over by Harley Quinn ., allowing the Joker to escape and take control of the facility. Batman quickly realizes that these events, including the Blackgate fire, are all part of the Joker's plan, and that the Joker bribed a security guard to let him escape. The Joker threatens to detonate several bombs scattered across Gotham if anyone tries to enter Arkham, forcing Batman to work alone; however, he manages to enlist the cooperation of Commissioner Gordon and other loyal guards after Batman frees them. In addition to them, the Oracle manages to help you navigate the island with the radio. Batman gains access to an adjunct Batcave he built years earlier.
