S03E22: 'Through The Looking Glass'

The island's survivors learn from Karl that The Others plan to ambush their camp and make use of Juliet's markings on the tents of the pregnant women whom they want to kidnap for research purposes. The tents are filled with dynamite in a bid to counter attack The Others and Sayid, Bernard and Jin stay behind with guns to fire at them from afar. However, one of the tents doesn't detonate and the trio is captured, although several Others are killed.

Charlie dives down to the 'Looking Glass' underwater station and is captured by two female Others, who subsequently interrogate him. On Ben's orders, Mikhail arrives and kills the two Others, but is shot through the chest by Desmond, who has been hiding within the station. The signal jammer is disabled and Penelope Widmore immediately sends a video message, telling Charlie she does not know about Naomi.

However, Mikhail intervenes and seals Charlie's fate by blowing up a window with a grenade, leading to Charlie's drowning as predicted. Before he dies, he tells Desmond that Penny is not on board the nearby boat. Meanwhile, Locke has a vision of Walt just as he's about to end his own life.

The rest of the camp heads to the radio tower to try to use Naomi's transmitter. On their way, they hear an explosion and soon Ben and Alex confront their group. Ben reveals that Naomi is an imposter and urges them not to contact her boat, while using the captured trio as leverage. Jack refuses and hears three shots via Ben's radio that lead the group to believe their fellow survivors have been shot.

However, Sawyer and Juliet, who returned to the camp, hooked up with Hurley and his van to defeat The Others and save the captives. At the same time, Ben is tied up and Rousseau meets her long-lost daughter Alex.

At the radio tower, the signal is unjammed but Locke arrives on the scene and suddenly kills Naomi and tells them not to contact the boat. Jack resists and sends a message, with the reply from the boat stating that they will be sent help.

Jack's frequent flashbacks, depicting his dishevelled state, are revealed to be flashforwards. He visits the memorial service of an unnamed person he used to know, then meets up with Kate in the dark of the night to tell her that they should never have left the island.