Batman: Arkham City is a 2011 action-adventure video game developed by Rocksteady Studios and released by Warner Bros. Interactive Entertainment for the PlayStation 3 and Xbox 360 video game consoles, and Microsoft Windows. Based on the DC Comics superhero Batman, it is the sequel to the 2009 video game Batman: Arkham Asylum and the second installment in the Batman: Arkham series. Written by veteran Batman writer Paul Dini with Paul Crocker and Sefton Hill, Arkham City is based on the franchise's long-running comic book mythos. In the game's main storyline, Batman is incarcerated in Arkham City, a massive new super-prison enclosing the decaying urban slums of fictional Gotham City. He must uncover the secret behind Arkham's sinister scheme, "Protocol 10", while protecting inmates from the notorious criminals housed there. The game's leading characters are predominantly voiced by actors from the DC Animated Universe, with Kevin Conroy and Mark Hamill reprising their roles as Batman and the Joker, respectively.