Call of Duty: Zombies is a first-person shooter video game developed by Ideaworks Game Studio, and published by Activision for iOS. It is a spin-off of the Call of Duty series, and based on the Zombie mode of Call of Duty: World at War. The game was released worldwide on November 16, 2009. The game allows for multiplayer cooperative gameplay locally via an ad hoc Wi-Fi or Bluetooth network, or globally via the internet. It also comes with the three other maps, Verrückt, Shi No Numa, and Der Riese. A sequel to the game, Call of Duty: Black Ops – Zombies has been published by Activision. The game's setting originally takes place in a German bunker (Nacht der Untoten) during World War II from the viewpoint of a US Marine. SS soldiers who have become zombies attempt to infiltrate the bunker and attack the players, and the players must defend themselves in the process.