The harrowing first 48 days in the lives of the tail section survivors are revealed. Flashbacks reveal the point of view of Ana-Lucia, Mr. Eko, Bernard and Libby and other survivors as they landed on the other side of the island on the beach. As the days progress danger hits their camp as well when “The Others” start taking people against their will. As the survivors race inland, trying to stay a step ahead of The Others, they realize that someone among them wasn’t on Flight 815.
Jack, Locke and Kate learn more secrets about the hatch. Meanwhile, after being beaten and taken captive, Sawyer, Michael and Jin wonder if their captors are fellow survivors or the dreaded “Others.” Flashbacks reveals more of Locke’s past in this episode as well as the introduction of Helen (guest star Katey Segal) who shakes things up even more with her revealing personality and past.
The Others prevent Sawyer and Kate from escaping, leaving Sawyer perplexed by the extent of the measures taken to keep them imprisoned. Jack is asked to use his medical training to save the life of one of the Others. At the beach, Desmond’s strange behavior attracts attention. He begins to construct a mysterious device.
When Kate and Locke arrive at the Others’ camp, Ben promises to tell Locke the island’s secrets as long as he stops his destructive plan, and Kate’s reunion with Jack doesn’t go very well when she learns that the Others have offered him a deal. More of Locke’s troubled past is revealed.
Kate discovers that someone knows the secret of Aaron’s true parental lineage. Meanwhile, the dramatic shifts through time are placing the lives of the remaining island survivors in extreme peril.
Shannon’s inhaler runs out and Boone believes Sawyer has the remaining three in his stash. When Sawyer refuses to give them up, Jack and Sayid resort to torturing Sawyer until he agrees to reveal the location of the inhalers. In flashback we hear Sawyer’s story and find he is not who he says he is.
In order to prevent more loss of life, Hurley leads the other survivors to speak with the Man in Black. In the flash sideways, Hurley meets Libby, while Desmond continues his mission to let the Oceanic 815 passengers know of their lives on the island.
Ben unwillingly divulges information to Locke about the island, taking him on a journey to various locations including strange monuments and the mysterious Jacob. Back at the beach, Juliet’s secret is revealed. Flashbacks will show us the origins of DHARMA and the history of the island, including ‘the purge.’
Michael sets off into the jungle by himself determined to find Walt, but discovers that he is not alone. Meanwhile, Sawyer and Jin are ordered by their captors to take them to their camp, and Sun frantically searches for her missing wedding ring. In flashbacks this episode reveals more of Jin’s life before ending up on the island.
Hurley and Sayid are on the run from the cops after stumbling into trouble at the safehouse; the island survivors come under attack by unknown forces; and an old friend offers some shocking advice to Kate in order to ensure that “the lie” remain a secret.
Having escaped the “creature” and retrieved the plane transceiver, a group of the survivors travel to higher ground so they can transmit a signal. En route, they receive a mysterious transmission and encounter another of the island’s inhabitants. Meanwhile, back at camp, Jack tends to a wounded man who reveals a secret about Kate.
The season 3 finale finds the castaways preparing for an invasion by the slightly less mysterious Others, while Charlie and Desmond find more than they were looking for in the underwater “Looking Glass Hatch”.
Richard Alpert’s back story is shown: In 1867, he is brought to the island on the Black Rock as a slave. He makes a deal with Jacob to be his representative in exchange for immortality. In the present day, Hurley convinces him to help the candidates replace Jacob and stop the Man in Black from leaving the Island.
After finding an exhausted Michael in the forest, Jack and Kate bring him back to the main camp. When he finally wakes up, Michael has some new details about “The Others.” Also, a lovestruck Hurley plans a date for Libby.
When Charlie’s vividly surreal dreams lead him to believe Claire’s baby, Aaron, is in danger, Locke suspects Charlie may be using again. Meanwhile, Sawyer encourages Hurley to act on his attraction to Libby.
Claire has an idea to send a message to the outside world. Charlie, however, is resistant to the idea, and Desmond tries to sabotage the plan. As Claire tries to get the truth behind their actions out of the pair, she remembers traumatic events from her past. Meanwhile, the rescue party encounters a dangerous obstacle.
Jack is nearly delirious from lack of sleep and struggles to overcome the haunting events that brought him to Australia and, subsequently, to the island. Meanwhile, Boone gets caught in a treacherous riptide trying to save a woman who went out swimming. A pregnant Claire’s health takes a bad turn from lack of fluids, and a thief may have stolen the last bottles of water. Veronica Hamel guest-stars as Jack’s mother, Margo.
Also, Jack flashes back at 12 years old, to find himself on the playground in an altercation with a bully, who ultimately beats him up, and later learns a life lesson from his father.
Kate goes to extreme measures to save Ben’s life when Jack refuses to help. Meanwhile, Kate begins to tell the truth about the lie in order to protect Aaron.
After the remaining survivors are reunited, Sawyer and Jack hatch a plan to divert the Man in Black’s attention and leave the island without him on Widmore’s submarine, but disastrous consequences await them. In the flash sideways, Jack investigates the cause of Locke’s paralysis and offers treatment.
The season 3 finale finds the castaways preparing for an invasion by the slightly less mysterious Others, while Charlie and Desmond find more than they were looking for in the underwater “Looking Glass Hatch”.
