This episode will shed more light on why Eko took a mysterious 40-day vow of silence, and possibly information on his stick. Also, Claire begins to lose faith in Charlie after Eko begins to question him about the Virgin Mary statue, and Kate gives the recovering Sawyer a much-needed haircut.
When the hatch suddenly takes on a life of its own, Locke is forced to enlist the help of an unlikely ally to control the matter. Meanwhile, Ana Lucia, Sayid and Charlie go off into the jungle to find out the truth about Henry Gale and see if there really is balloon craft out there in the jungle that carried him and his wife to the island.
Sun comes to the realization that she might be pregnant. She struggles on whether to tell Jin about the situation. Meanwhile, with no success from Jack or Sayid, Ana-Lucia is called in by Locke to interrogate the new prisoner Henry Gale to get more information out of him about the balloon that he and his wife supposedly landed on the island with.
After Desmond rescues Claire from drowning, Charlie gets Hurley to help him find out why Desmond has seemed able to predict the future. Desmond recalls exactly what took place in the moments after he turns the key, where he experienced a strange vision of his life prior to his Army days.
The face-off between the survivors and the freighter people continues, and the Oceanic Six find themselves closer to rescue.
After Sun is attacked, some of the survivors begin to think that one of the “other survivors” might be one of “The Others.” When French woman Danielle Rousseau leads Sayid to a mysterious captive in the jungle, he becomes determined to find out if he is one of “The Others”. Meanwhile, Sawyer discovers Hurley’s potentially devastating breach of the survivors’ trust and blackmails him into helping track an elusive island creature that won’t leave Sawyer alone.
Suspicions about a possible breach intensify after Ben is taken from the infirmary, and a reluctant Miles is forced to work with Hurley when he’s asked to deliver an important package to a top Dharma official.
Jack, Kate, and Sawyer are prisoners of the mysterious “Others.” After their captors drug them and take blood samples, they are held in separate areas. The camp leaders–Ben (Henry Gale), Mr. Friendly and a new woman, Juliet–try to make the castaways adjust to their new circumstances.
Flashbacks reveal more about Jack’s past with his father and his wife Sarah.
A determined Michael convinces Jack and several castaways to help him rescue Walt from “The Others.” With Jack away, Locke is left in charge of the hatch and must decide if he should believe Henry and not push the button, risking everyone’s safety. Meanwhile, the events that happened to Michael after he left are finally revealed. Meanwhile, Charlie struggles with Eko’s decision to discontinue building the church.
A delirious Eko wrestles with past demons; some of the castaways go to the Pearl station to find a computer they can use to locate Jack, Kate and Sawyer; Jack does not know who to trust when two of the Others are at odds with each other.
On the island, the Man in Black attempts to recruit Sawyer in his attempt to leave the island, while an impromptu funeral is held for the real Locke. In the flash sideways, Locke is fired from his job and becomes a substitute teacher.
After the missing Claire returns with no recollection of what has happened since before she boarded the doomed Oceanic flight 815, Jack and Locke formulate a plan of defense against her kidnapper, the mysterious Ethan (guest-star William Mapother), who threatens to kill off the other survivors one by one unless Claire is returned to him. Meanwhile, the disappointment Charlie feels when Claire does not remember him triggers recollections of a woman he had let down in the past.
Jack and Kate find themselves at odds over the direction to take to save their fellow island survivors, Locke further solidifies his stance as leader of “The Others,” and Sawyer and Juliet come under scrutiny from the Dharma Initiative.
Jack tries to discover the identity of a body that has washed ashore. Meanwhile, Locke’s camp is attacked by Ben’s adversaries.
Sun and Jin’s lives are put in danger when Sayid tries to locate Jack and the other missing castaways. Sayid also creates a plan in order to get the attention of the “Others” on the beach. Meanwhile, Henry (i.e. Ben) gives Jack an offer that is very tempting in exchange for his cooperation. Lastly, Kate and Sawyer must adjust to harsh conditions that are being forced upon them by “The Others.”
Jacob and the Man in Black are revealed to be twin brothers. They are raised by a mysterious woman who is charged with protecting the island. As revenge for the murder of their adoptive mother (who killed their real mother), Jacob throws his brother into the source of electromagnetism after being made the island’s guardian, which transforms the Man in Black into the smoke monster.
Rose is surprisingly and vehemently opposed to Bernard’s plan to create an S.O.S. signal; romantic sparks are rekindled between Jack and Kate when they trek into the jungle to propose a “trade” with “The Others”; and Locke begins to question his faith in the island.
On the island, Widmore subjects Desmond to a large amount of electromagnetic energy as an experiment. In the flash sideways, Desmond, with the aid of Charlie, starts to have visions of his life in the original timeline.
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.
The survivors are jolted awake in the middle of the night when wild island beasts (which are wild boars) invade the beach encampment. Kate and Michael join the mysterious Locke on a hunt for food — and a shocking secret about Locke is revealed. On the hunt for food someone is injured. Meanwhile, some survivors are horrified by Jack’s plan for the dead bodies still scattered among the wreckage — he wants to burn them. Jack sees someone that’s not there, and we find out that one of the survivors was not able to walk but now he can.
