Sawyer buries Juliet with Miles while Jack, Kate, Hurley and Jin bring Sayid to the underground of the temple; out of the blue, they are attacked by mysterious natives. Hurley shows the guitar case that Jacob gave to him and save the group. Sawyer asks Miles to tell him what Juliet wanted to tell him. Sayid is drowned by the natives and dies. Sawyer and Miles are captured by the natives and Hurley is interrogated and tells that Jacob is dead, panicking the natives. John attacks Richard in front of his group. Meanwhile, in a parallel reality, Kate succeeds to escape ...
Jacob sends Hurley on a mission across the island, but Jack must accompany him. In Los Angeles, Jack's difficult relationship with his son is revealed. Meanwhile, Jin discovers that Claire thinks the people at the temple stole her son.
Claire arrives at the temple and warns the inhabitants that the being inhabiting Locke wants to talk, but Dogen sends Sayid to kill him instead. In Los Angeles, Sayid saves his brother, who is in trouble with a loan shark.
Ilana prepares to kill Ben after Miles reveals that Ben killed Jacob. In Los Angeles, Ben contemplates a power play at his high school. Meanwhile Richard and Jack share their secrets and experiences with Jacob and form an alliance.
Locke sends Sawyer on a recon mission to the other island, where he runs into Charles Widmore and his submarine crew. In Los Angeles, Sawyer works as a police officer obsessed with finding the conman who destroyed his family.
The mysteries behind Richard Alpert's arrival to the island, his immortality, and his alliance with Jacob are revealed--plus more details about the purpose of the island and the relationship between Jacob and the smoke monster.
Sun and Jin's search for each other is interrupted when Widmore's crew kidnaps Jin, and Locke heads to the other island to bring him back. In Los Angeles, Jin's job for Sun's father is sidetracked when his money is taken at customs.
Charles Widmore brings Desmond back to the island so that he can conduct a dangerous electromagnetic experiment, which sends him back to the alternate reality in Los Angeles, a reality where he has never met Penny.
With Jack's help, Locke rescues the candidates from Widmore's compound, but their plans for leaving the island are forced to change. In Los Angeles, Jack tries to convince Locke to try an experimental surgery for his paralysis.
Locke searches for Desmond to achieve his goal of destroying the island. Jack, the newly-appointed "protector" of the island, sets out to stop him. In Los Angeles, the survivors slowly reunite and recall their island experiences.