As the stranded passengers work to survive, the island begins to reveal that it has mysterious of its own. The discovery of a transceiver in the wreckage raises hopes of a rescue.
Hunting for food for the survivors with Kate and Michael, Locke recalls the circumstances that led him to his new destiny. Jack recommends burning the planet's fuselage, along with those who did not survive.
Jack is haunted by the grim events that brought him to Australia, and seeks to resolve the outstanding issues he has with his father. Claire's health takes a turn for the worse, and the last of the water goes missing.
Michael is brutally beaten by Jin, and only his wife knows the true reason for the unprovoked attack. The leaders of the encampment argue about whether or not to relocate to a fresh water source inland.
A cave-in leaves Jack trapped, as Charlie's drug withdrawals drag up his once-hopeful past as a musician. Sayid leads a team to try and find the source of the French woman's transmission.
Shannon suffers an asthma attack, forcing Sayid and Jack to go to desperate -- and brutal -- measures to convince Sawyer to give up her life-saving medicine.
Claire is plagued by disturbing dreams that someone is trying to harm her baby, and remembers the early days of her pregnancy and how she ended up on the plane. Hurley conducts a census of the survivors, only to make a startling discovery.
A search party ventures into the deadly jungle to try and find Claire and Charlie, who have been kidnapped. Jack recalls a falling out with his father, a fellow surgeon, while Locke and Boone make a new discovery in the jungle.
Kate and Sawyer fight over a locked case found from the crash, which holds a key to her past crimes. Sayid seeks Shannon's help in translating the French woman's cryptic notes.
Locke puts Boone and Shannon into mortal danger when he learns that Boone intends to share their new secret, revealing the truth about the siblings' relationship.
Claire returns from the jungle with no memory of the weeks since the crash, but her kidnapper threatens to kill them off one by one unless Claire is returned. Charlie recalls a time when he tried to go straight.
Jin and Sun's marriage is on the line when he suspects that she has become involved with Michael -- who is furious when his escape raft is set aflame. Shannon and Sayid consider taking their relationship to the next level.
Locke's obsession with opening the hatch leads him and Boone to an undiscovered plane crash, and drags up memories of an encounter with his long-lost father.
Suspicions are cast when Kate makes a play for a spot on the raft, and Michael is poisoned. Kate is haunted by her past life on the run from the law, and the fate of a dear friend.
As Michael and the others prepare to launch the raft, the French woman arrives on the beach with a grave warning: the "Others" are coming for them all. Jack and Locke join Danielle in search of a stash of dynamite.
Jack, Kate, Locke, and Hurley attempt to transport dynamite to open the hatch as a place of refuge for the survivors, while the raft sails to search for rescue. Charlie and Sayid go in search of Rousseau when she abducts Claire's baby.
