Lost is an American live-action television series. It follows the lives of plane crash survivors on a mysterious tropical island, after a commercial passenger jet flying between Sydney and Los Angeles crashes somewhere in the South Pacific. Each episode typically features a primary storyline on the island as well as a secondary storyline from another point in a character's life, though other time-related plot devices change this formula in later episodes. The pilot episode was first broadcast on September 22, 2004, and since then five full seasons have aired, with a sixth currently in progress set to finish on 23 May 2010. The show airs on the American Broadcasting Company in the United States, as well as on regional networks in many other countries.