Charlie’s dying message casts doubt on the intentions of the people that Jack believes to be their rescuers. A power struggle ensues between Jack, who wants to leave the island, and Locke, who thinks that they’re supposed to stay.

Watch "Season 4 Episode 1 : ‘The Beginning of the End’"

Jack and the survivors wait for Charlie to turn off The Others’ signal-jamming device, not knowing that he has been captured at the Looking Glass station. In addition, Sayid, Jin and Bernard are captured after The Others invade the camp.

Watch "Season 3 Episode 22 : ‘Through the Looking Glass’"

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.

Watch "Season 3 Episode 21 : ‘Greatest Hits’"

As Ben takes Locke to see Jacob and reveal the island’s secrets, Ben’s background on the island is exposed–as well as what happened to the Dharma Initiative.

Watch "Season 3 Episode 20 : ‘The Man Behind the Curtain’"

Locke tells Sawyer that he needs to come with him to kill Ben. But the man Locke wants him to kill is actually his father–who also happens to be a figure from Sawyer’s past.

Watch "Season 3 Episode 19 : ‘The Brig’"

An unlikely person helps Desmond save the life of the mysterious woman who crashed onto the island, and Juliet helps Sun find out whether she conceived on the island or before the plane crash.

Watch "Season 3 Episode 18 : ‘D.O.C.’"

Desmond’s latest fragmented vision suggests that his old girlfriend, Penny, will crash-land onto the island. Desmond organizes a posse of himself, Hurley, Jin, and Charlie to come along with him into the jungle expecting Penny to parachute onto the island. But the vision also suggests that Charlie will die by stumbling upon a trip-wire if he comes along with them.

Watch "Season 3 Episode 17 : ‘Catch-22′"

Jack takes Juliet back to their camp after being abandoned by The Others. However, nobody else at the camp trusts her or wants her there, until she saves Claire’s life.

Watch "Season 3 Episode 16 : ‘One of Us’"

With their secret location now compromised, The Others abandon camp and take Locke with them. But they also leave Juliet behind, handcuffed to Kate in the middle of the jungle.

Watch "Season 3 Episode 15 : ‘Left Behind’"

Nikki and Paulo are two more of the castaways with a past just like any of the others. What have they been doing since the plane crash?

Watch "Season 3 Episode 14 : ‘Exposé’"

Jack tells Kate that he has made a deal with The Others and is leaving via submarine tomorrow. But Locke blows up the submarine before Jack can leave, after having a long conversation with Ben about the island’s powers.

Watch "Season 2 Episode 13 : ‘The Man from Tallahassee’"

Claire launches a plan to use migratory birds to send a message, but she doesn’t understand why Desmond keeps sabotaging it. Elsewhere on the island, Sayid, Locke and Kate scale The Others’ protective perimeter and discover their camp.

Watch "Season 3 Episode 12 : ‘Par Avion’"