The aftermath from Juliet's detonation of the hydrogen bomb is revealed. '

The aftermath from Juliet's detonation of the hydrogen bomb is revealed. '

The aftermath from Juliet's detonation of the hydrogen bomb is revealed. '

Locke goes in search of help to further his cause.

Hurley tries to persuade Jack to go with him on an unspecified mission; Jin has an encounter with an old friend.

Dogen asks Sayid to make a decision, while Locke sends Claire to give the temple inhabitants a warning. Meanwhile, in another life, Sayid must come to the aid of his family and meets a familiar face.

Ilana discovers the extent of Ben's involvement in Jacob's death, while Hurley and Jack meet Richard. In another life, Dr. Ben Linus, a high school history teacher, must make an important choice.

Locke sends Sawyer to Hydra Island to investigate the plane, but he encounters Widmore's people instead. Meanwhile, in another life, Sawyer is a police detective looking for Anthony Cooper, the man responsible for his father's death.

Richard Alpert faces a difficult choice, and remembers how he came to the island... over a hundred years ago.

Widmore's people abduct Jin, and Locke vows to get him back. Meanwhile, in another life, Jin and Sun come together but Sun's father seeks to separate them... permanently.

Desmond wakes up to discover he's back on the island

Hurley tries to determine what he has to do to save everyone, and who to listen to. Meanwhile, Locke meets Desmond, Richard insists on blowing up the plane, and in another life, a rich and successful Hurley meets a woman from an insane asylum who insists she knows him.

As alliances are forged and broken as the Locke and Jack camps merge. Widmore delivers his ultimatum. Meanwhile, Jack makes a decision, Jim and Sun are reunited, and in another life, the candidates draw ever closer together.

Locke, Jack, and Sayid free the prisoners and attempt to escape the island, but Locke has his own plans. Meanwhile, in another reality, Jack tries to learn why Locke won't seek a cure for his condition.

The origins of Jacob and the Man in Black are revealed.

Locke gains a new follower and goes to confront Widmore. Meanwhile, Jacob meets with the candidates and one of them must choose their destiny. And in another life, Locke makes a decision while Desmond gathers the others.

Jack, the new protector of the island, meets with Locke and they go past the bamboo field with Desmond to visit the heart of the island. Meanwhile, in another life, Desmond and Hurley work with Sayid and Kate to reunite with some familiar faces and get everyone to the concert.

The Man in Black's final fate is determined, and one survivor must make the ultimate sacrifice to save the island. Meanwhile, in another life, the ones who might have been the survivors gather for a final time.