In the season premiere, one of the castaways is chosen to descend into the mysterious hatch, and Shannon stumbles upon a shockingly familiar face in the jungle. A Jack-centric episode.

With the abduction of Walt fresh on their minds and their raft destroyed, Michael and Sawyer fight for their lives and discover a new predator in the roiling ocean. Meanwhile on land, Locke must descend into the hatch when one castaway goes missing inside. A Michael-centric episode.

Jack, Locke and Kate learn more secrets about the hatch. Meanwhile, after being beaten and taken captive, Sawyer, Michael and Jin wonder if their captors are fellow survivors or the dreaded Others. A Locke-centric episode.

Hurley struggles with an assigned task inside the hatch. Sawyer, Michael and Jin learn the identities of their captors. Claire uncovers a startling piece of information about the fate of the raft. A Hurley-centric episode.

Michael sets off into the jungle by himself determined to find Walt, but discovers that he is not alone. Meanwhile, Sawyer and Jin are ordered by their captors to take them to their camp, and Sun frantically searches for her missing wedding ring. A Jin-Sun-centric episode.

Sawyer's wound becomes life-threatening as he, Michael and Jin make their way through the interior of the island with the tail section survivors. Meanwhile, Shannon is once again haunted by visions of Walt. Also, Shannon's shocking past of her former marriage as well as her manipulation of people prior to the crash are revealed. Plus, there is the revelation on the death of Shannon's father who ended up in the hospital where Jack worked. Lastly, Charlie becomes jealous of Locke's interest in Claire. A Shannon-centric episode.

The first 48 days in the lives of the tail section survivors are revealed. Note: This episode is running 5 minutes longer than normal, making it end at 10:05

Tempers flare when Ana Lucia and her group stumble upon Sayid and the other castaways. An Ana Lucia-centric episode.

Kate's original crime that started her life on the run is revealed. The survivors lay Shannon to rest whilst Kate sleeplessly watches over a feverish Sawyer, leading her to question her sanity. Mr. Eko has a surprise for Locke regarding the hatch and Michael takes a closer look at the mainframe system. A Kate-centric episode.

We learn more about the mysterious Mr. Eko as he interrogates Charlie about the Virgin Mary statue, Claire begins to lose faith in Charlie when she discovers his secret, and Jack is an interested observer when Kate gives the recovering Sawyer a much-needed haircut. A Mr. Eko-centric episode.

Jack, Locke and Sawyer pursue a determined Michael after he heads into the jungle toward the dreaded Others in search of Walt. Meanwhile, Sun has a surprising reaction to Jin's desire to join the search party, and Hurley and Charlie commiserate over the age-old conundrum of what women want. A Jack-centric episode.

When Charlie, 's vividly surreal dreams lead him to believe Claire, 's baby, Aaron, is in danger, Locke suspects Charlie may be using drugs again. Meanwhile, Sawyer encourages Hurley to act on his attraction to Libby. Flashbacks will feature 8-year-old Charlie and 12-year-old Liam. A Charlie-centric episode.

Survivors fear that , The Others, may have returned when Sun is injured during a failed kidnapping attempt. Meanwhile, Sawyer is an amused but highly interested bystander when tension escalates between Jack, Locke, Kate and Ana Lucia. A Sawyer-centric episode.

When Rousseau leads Sayid to a mysterious captive in the jungle, he becomes determined to find out if he is one of the "Others." Meanwhile, Sawyer discovers Hurley's potentially devastating breach of the survivors' trust and blackmails him into helping track an elusive island creature that won't leave Sawyer alone. A Sayid-centric episode.

Aaron suddenly becomes very ill, and a desperate Claire, along with Kate and Rousseau, attempts a return to the scene of her kidnapping where she believes she might find the cure for baby Aaron's mysterious illness. Meanwhile, Jack and Locke must keep their prisoner a secret from the rest of the survivors. A Claire-centric episode.

Sun wrestles with the thought of telling Jin a newfound secret that threatens to upset the entire balance of the survivors, ' community. Meanwhile, Locke enlists Ana Lucia to interrogate the prisoner in order to extract more information than he, Jack or Sayid could. A Jin and Sun-centric episode.

When the hatch suddenly takes on a life of its own, Locke is forced to enlist the help of an unlikely ally. Meanwhile, Ana Lucia, Sayid and Charlie go off into the jungle to find out the truth about Henry. A Locke-centric episode.

Libby lends Hurley support when he begins to think the island is having a strange effect on him, and Locke, 's sense of purpose is shaken when the prisoner provides new information about the hatch. A Hurley-centric episode.

Rose is surprisingly and vehemently opposed to Bernard, 's plan to create an S.O.S. signal; romantic sparks are rekindled between Jack and Kate when they trek into the jungle to propose a trade with The Others; and Locke begins to question his faith in the island. A Rose-Bernard-centric episode.

Jack and Kate bring an exhausted Michael back to the camp, and with him, news about The Others. Meanwhile, Ana Lucia attempts to get the prisoner to confess, and Hurley plans a surprise date for Libby. An Ana Lucia-centric episode.

Mr. Eko enlists Locke to help find a secret location he believes houses answers to the island's mysteries. Meanwhile, Jack and the other survivors struggle to cope with the horrific situation in the hatch. An Eko-centric episode.

A determined Michael convinces Jack and several castaways to help him rescue Walt from the Others. Meanwhile, Charlie struggles with Eko's decision to discontinue building the church. A Michael-centric episode.

Desmond's return to the island opens up a whole box of revelations---particularly about life prior to his race and what went on during his three years inside the Swan Hatch. Meanwhile, Jack, Kate, Sawyer and Hurley go off toward the Others in search of Walt as Sayid, Sun and Jin begin reconnaissance of the north shore. As Locke and Eko battle over the 108 minute button, Desmond comes to a startling conclusion about the crash of Flight 815 and the purpose of the Swan Hatch. In the jungle, Michael's betrayal is revealed as Jack, Kate, Sawyer and Hurley are taken captive by the Others, and Sayid discovers the truth about the north shore camp. A Desmond-centric episode.

After discovering something odd just offshore, Jack and Sayid come up with a plan to confront "The Others" and hopefully get Walt back. Meanwhile, Eko and Locke come to blows as Locke makes a potentially cataclysmic decision regarding the "button" and the hatch