Jack and the survivors make contact with the freighter offshore, but tensions rise when a group from the ship arrives with unclear intentions. Led by physicist Daniel Faraday, the newcomers claim to be there to rescue them, but it soon becomes clear they have a hidden agenda. Locke, convinced the freighter crew poses a threat, takes a group of survivors to live at the Barracks, while Jack and the others stay on the beach, hoping for rescue. Meanwhile, Sayid allies with the freighter crew and learns that their leader, Charles Widmore, is searching for the island. Ben, now a prisoner, warns that Widmore's people will kill everyone.
As conflict escalates, the freighter team's mercenary leader, Martin Keamy, launches a brutal assault, killing several survivors in an attempt to capture Ben. Knowing he is the target, Ben unleashes the smoke monster on the attackers and ultimately escapes with Locke and Hurley. Meanwhile, Desmond and Sayid reach the freighter, only to find it rigged with explosives. Michael, who has been working on the ship to redeem himself, desperately tries to prevent its destruction. At the same time, Faraday attempts to ferry survivors to safety, but time is running out. Aboard a helicopter, Jack, Kate, Hurley, Sayid, Sawyer, Sun, and Aaron flee just as the freighter explodes, leaving Jin's fate uncertain.
In a final desperate act, Ben moves the island using an ancient wheel beneath the Orchid station, causing it to disappear before the eyes of those escaping. The helicopter crashes into the ocean, but the survivors are rescued by Penny's boat. To protect those left behind, they fabricate a lie about what happened, becoming known as the "Oceanic Six". In the future, Jack spirals into guilt and despair, realizing they were never meant to leave. Ben finds him and insists that the only way to make things right is for them all to return to the island.
As the new season begins, 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. But who can be trusted? Is rescue really as close as it seems?
Four strangers arrive on the island leaving the survivors to wonder if they are really here to rescue them, or if they have a different purpose.
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 decides to take matters into her own hands in order to get information out of the camp's hostage. However, this idea may cause a problem with the camp's new leader, Locke.
On the way to the freighter, the survivors on the helicopter hit some turbulence. This causes "side effects" with one of the passengers on board.
Juliet gets a surprising visit from someone from her past. She is given orders to stop Charlotte and Faraday from doing what they have set out to do. Back at the Barracks, Ben offers Locke an enticing deal.
Juliet decides to reveal some startling news to Jin when Sun decides to move to Locke's camp. On the freighter, Sayid and Desmond get to know the crew as they meet the ship's captain.
After Sayid encounters Michael, the story of how Ben's spy got to the freighter is finally revealed. Back at Locke's camp, Ben sends his daughter, Alex, to a safer place so that she may survive an approaching 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. 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 as Keamy takes action in his own hands.
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.