Combat focuses on chaining attacks together against numerous foes while avoiding damage, while stealth allows Batman to conceal himself around an area, using gadgets and the environment to silently eliminate enemies. The player is able to complete side missions away from the main story to unlock additional content and collectible items. Batman can freely move around the open world of Gotham City, interacting with characters and undertaking missions, and unlocking new areas by progressing through the main story or obtaining new equipment. The game is presented from a third-person perspective, with a primary focus on Batman's melee combat, stealth abilities, detective skills, and gadgets. Scarecrow, with the help of the mysterious Arkham Knight, is also able to unite Batman's greatest foes in an attempt to finally destroy Batman. Set nine months after the events of 2011's Batman: Arkham City, the game's main storyline follows Batman as he confronts Scarecrow, who has launched an attack on Gotham City, causing a citywide evacuation. Written by Sefton Hill, Ian Ball and Martin Lancaster, Arkham Knight is inspired by the long-running comic book mythos. Based on the DC Comics superhero Batman, it is the successor to the 2013 video game Batman: Arkham Origins, and the fourth main installment in the Batman: Arkham series. Batman: Arkham Knight is a 2015 action-adventure game developed by Rocksteady Studios and published by Warner Bros.