The End

On the island, Jack becomes the island's new guardian and sets out to save Desmond as he is the island's fail safe. Locke and Jack take Desmond to the heart of the island – home to the light that must never go out. The rivals want Desmond to go down into the cave, with Jack thinking Desmond's powers will save the island and Locke believing they will destroy it.

Desmond climbs down and pulls out a plug in a pool of radioactive water. This causes lave to begin flowing up and the island to begin to self-destruct. Locke is triumphant, however he is no longer immortal. After a scuffle with Jack, Locke is shot dead by Kate.

Jack rushes back to the cave and puts the plug back in place. The island is saved, but Jack is killed by the radioactive power that only Desmond can survive.

Kate, Miles, Sawyer, Clare, Richard and Frank leave the island by plane, while Hurley remains as the island's new guardian with Ben as his deputy.

In the alternate timeline, all the characters finally come together. Sawyer and Juliet remember their island romance, as do Jack and Kate and the other couples.

They gather at a chapel, where Christian Shepherd tells Jack that this timeline is a holding area, not unlike purgatory, where the spirits of all the Losties have been waiting since their deaths, either on the island or years after they left.

With Jack ready to cross over and the whole gang reunited, the chapel's doors open and the light of the island – that Jack and the Losties worked together to keep alight while on the island – floods the room as they blissfully move on into another life.