Halo 3: ODST ("Orbital Drop Shock Troopers") is a 2009 first-person shooter video game developed by Bungie and published by Microsoft Game Studios. It is part of the Halo franchise, and was released on the Xbox 360video game console on September 22, 2009. Players assume the roles of United Nations Space Command soldiers, known as "Orbital Drop Shock Troopers" or ODSTs, during and after the events of Halo 2. In the game's campaign mode, players explore the ruined city of New Mombasa to discover what happened to their missing teammates in the midst of an alien invasion. In the "Firefight" multiplayer option, players battle increasingly difficult waves of enemies to score points and survive as long as possible; Halo 3's multiplayer is contained on a separate disc packaged with ODST.