Trying to kick his drug habit with encouragement from Locke, Charlie
starts to go through heroin withdrawl, struggling with his resolve.
Jack is trapped in a cave-in, and Charlie becomes trapped with him when
the first rescue tunnel collapses as well. Kate, Sayid, and Sawyer
attempt to triangulate the position of the distress signal coming from
the island. Charlie has flashbacks of his rock band, and his decent
into drug abuse.