Episode 26 of "Lost"
s02e01 Man of Science, Man of Faith

The second season starts where the survivors have left off with Jack, Locke and others going down the hatch and finding out what is under there. One of the castaways is chosen to descend into the mysterious hatch, and Shannon stumbles upon a shockingly familiar face in the jungle. The band of friends, family, enemies and strangers must continue to work together against the cruel weather and harsh terrain if they want to stay alive on the island. But, as they have discovered during their forty-plus days on the island, danger and mystery loom behind every corner, and those they thought could be trusted may turn against them. Even the most beloved heroes have secrets. Lastly, Jin, Michael and Sawyer survive their boat attack from "the others" while Walt is still missing out at sea.