The fourth season of the American serial drama television series Lost commenced airing on the American Broadcasting Company Network in the United States, and on CTV in Canada on January 31, 2008 and concluded on May 29, 2008. The season continues the stories of a group of over 40 people who have been stranded on a remote island in the South Pacific, after their airplane crashed there more than 90 days prior to the beginning of the season. According to Lost's executive producers/writers/showrunners Damon Lindelof and Carlton Cuse, there are two main themes in fourth season: "the castaways' relationship to the freighter folk" and "who gets off the island and the fact that they need to get back". Lost came under scrutiny from critics in its third season, but the fourth season was acclaimed for its flash-forwards, pace and new characters.
The season was originally planned to contain 16 episodes; eight were filmed before the start of the 2007–2008 Writers Guild of America strike. Following the strike's resolution, it was announced that only five more episodes would be produced to complete the season; however, the season finale's script was so long that network executives approved the production of a 14th episode as part of a three-hour season finale split over two nights. The fourth season aired Tuesdays at 9:00 pm from January 31 to March 20, 2008 and at 10:00 pm from April 24 to May 15, 2008. The two-hour finale aired at 9:00 pm on May 29, 2008. Buena Vista Home Entertainment released the season on DVD and Blu-ray Disc under the title Lost: The Complete Fourth Season – The Expanded Experience on December 9, 2008 in Region 1; however, it was released earlier—on October 20, 2008—in Region 2.
The survivors feel that rescue is close at hand, but they don't know whether or not to believe Charlie's final message that the people claiming to liberate them are not who they seem to be. As unlikely alliances are formed, those they thought could be trusted may turn against them, as the enemy of their enemy becomes their friend.
The survivors begin to question the intentions of their supposed rescuers when four strangers arrive on the island.
Locke's hostage may be the key to getting off the island, so Sayid and Kate go in search of their fellow castaway in an attempt to negotiate a peaceful deal.
Kate needs to get information out of the hostages, but it may jeopardize her standing with Locke -- as well as with Sawyer. Meanwhile in the future Kate's Court hearings take place.
Sayid and Desmond hit a bit of turbulence on the way to the freighter, which causes Desmond to experience some unexpected side effects.
Juliet receives an unwelcome visit from someone from her past and is given orders to track down Charlotte and Faraday in order to stop them from completing their mission -- by any means necessary. Meanwhile, Ben offers Locke an enticing deal.
Juliet is forced to reveal some startling news to Jin when Sun threatens to move to Locke's camp. Meanwhile, Sayid and Desmond begin to get an idea of the freighter's crew when they meet the ship's captain.
Sayid confronts Ben's spy on the freighter, and Ben urges daughter Alex to flee Locke's camp in order to survive an impending attack.
Jack tries to discover the identity of a body that has washed ashore. Meanwhile, Locke's camp is attacked by Ben's adversaries.
Kate and Juliet must learn to work together when Jack's health is seriously compromised, and something goes wrong as Sawyer, Claire, Aaron and Miles continue their trek away from Locke's camp and back to the beach
Locke finds out where Jacob's cabin is. Life on the freighter becomes dangerous.
Sayid goes back to the island to bring the rest of the people to the freighter. Ben, Locke, and Hurley go to another Dharma station in order to "move the island".
The face-off between the survivors and the freighter people continues, and the Oceanic Six find themselves closer to rescue.
As the face-off between the survivors and the freighter people continues, the Oceanic Six find themselves closer to rescue.