Jack, Kate, and Sawyer are prisoners of the mysterious "Others." After their captors drug them and take blood samples, they are held in separate areas. The camp leaders--Ben (Henry Gale), Mr. Friendly and a new woman, Juliet--try to make the castaways adjust to their new circumstances.

Flashbacks reveal more about Jack's past with his father and his wife Sarah.

Jack has the Others in a desperate situation as he holds Ben's life in his hands. Meanwhile, Kate and Sawyer try to escape from their captors. Flashbacks reveal Juliet's past as a medical researcher in Miami.

As Kate and Sawyer journey back to the main island with Karl, who is exhibiting effects of the brainwashing video, they argue over whether to go back and save Jack. On Hydra island, as Juliet's fate rests in his hands and a power struggle within the Others ensues, Jack recollects the time he spent in Phuket, Thailand and his relationship with Achara, a mysterious tattoo artist.

While Jack devises a plan to do away with "The Others" once and for all, Sayid uncovers a flaw in "The Others'" system that could lead to everyone's rescue. But it requires Charlie to take on a dangerous task that may make Desmond's premonition come true.

A Charlie-centric episode.

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".

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".

They thought they had met the enemy. They thought they had seen evil. They thought wrong. As the new season begins, the survivors feel that rescue is close at hand, but they don't know whether or not to believe Charlie's final message that the people claiming to liberate them are not who they seem to be. As unlikely alliances are formed, those they thought could be trusted may turn against them, as the enemy of their enemy becomes their friend. But who can be trusted? Is rescue really as close as it seems?

The survivors begin to question the intentions of their supposed rescuers when four strangers arrive on the island.

Sayid confronts Ben's spy on the freighter, and Ben urges daughter Alex to flee Locke's camp in order to survive an impending attack.