Bernard tries to convince the survivors to build a S.O.S. signal with rocks on the sand, hoping to be seen by a satellite or an airplane. His first encounter with Rose, who was terminal, and their romance, are disclosed through flashbacks. Bernard never gives up searching for the cure of Rose before crashing the island. Meanwhile, Jack invites Kate to join him in the woods to propose to “The Others” a trade between Henry and Walt. John Locke is intrigued with the words of Henry about the unnecessary use of the computer. Is Henry playing him for a fool? Elsewhere, Charlie assists Mr. Eko in building a proposed church for the rest of the survivors.
Survivors fear that “The Others” may have returned when Sun is injured during a failed kidnapping attempt. Meanwhile, Sawyer is an amused, but highly interested, bystander when tension escalates between Jack, Locke, Kate and Ana Lucia over control of the hatch computer, and the storage of the weapons.
Kate’s original crime that started her life on the run is revealed. Meanwhile, the survivors lay one of their own to rest, Kate sleeplessly watches over a feverish Sawyer, and Mr. Eko has a surprise for Locke regarding the hatch.
The harrowing first 48 days in the lives of the 23 tail section survivors are revealed, formally introducing Ana-Luca, Mr. Eko, Libby, Cindy, Bernard, and Goodwin detailing the first terrifying days and battling the dreaded “others”, leading to their numbers dwindling, their hikes though the jungle, and meeting with Jun, Michael and Sawyer.
Sawyer’s wound becomes life-threatening as he, Michael and Jin make their way through the interior of the island with the tail section survivors, Ana-Lucia, Mr. Eko, Bernard, Libby, and flight attendant Cindy. Meanwhile, Shannon is once again haunted by visions of Walt, but she cannot convince a skeptic Sayid that her visions are real. More of Shannon’s background story shows her difficult relationship with her late half-brother Boone and further detailing how her step-mother financially cut her off after the death of their father. Also, Charlie becomes jealous of Locke’s interest in Claire, while Locke learns that Charlie took a heroin stuffed porcelain statue from the Beechwood plane wreck.
Disturbing memories from Hurley’s past cause him to struggle with a task he’s assigned inside the hatch to watch over the food storage locker. Meanwhile Sawyer, Michael and Jin discover the identities of their captors whom are what’s left of a group of two dozen Flight 815 survivors from the tail end of the plane led by the tough minded Ana-Lucia Cortez who insists they walk to a more secure location. Claire uncovers a shocking piece of information about the fate of the raft when the message bottled washes ashore.
Desmond has another vision of Charlie’s death, but this time his death ultimately will result in Claire’s rescue. Meanwhile, the survivors discover that an attack by the others is even more imminent than originally expected.
Forty-eight survivors of an airline flight originating from Australia, bound for the U.S., which crash-lands onto an unknown island 1000 miles off course, struggle to figure out a way to survive, why trying to find a way to be rescued.
The survivors left on the island, now led by Sawyer after Locke’s departure, find themselves back in the 1970s, where they are now forced to become members of the Dharma Initiative.
In order to avoid being killed, Ben promises to offer proof to Sun that Jin is still alive. On the island, Jin meets up with the survivors as Locke reaches The Orchid and fulfills his mission.
