After the Joker assaults Gotham City Hall, he is caught by Batman and taken to Arkham Asylum, which temporarily houses many members of the Joker's gang, who were transferred after a fire at Blackgate Prison. Believing the Joker allowed himself to be captured, Batman accompanies him into the asylum. The Joker's plan is revealed as Harley Quinn takes control of the security and the Joker escapes into the facility, aided by a corrupt guard who kidnaps Commissioner Gordon. The Joker threatens to detonate bombs hidden around Gotham City if anyone tries to enter Arkham, forcing Batman to work alone. Tracking Quinn to the medical facility to rescue Gordon, Batman is exposed to the Scarecrow's fear toxin and hallucinates, seeing Gordon's death and the corpses of his parents talking to him. After fighting off Scarecrow, Batman finds and subdues Quinn before rescuing Gordon. The Joker then directs Batman to the captured Bane, who has been experimented on by asylum doctor Penelope Young. The Joker frees Bane and Batman is forced to fight him, during which Quinn escapes. Afterward, he goes to a secret Batcave installation he had hidden on the island, where Batman restocks his gadgets.