Season 5 opener: Jack and Ben try to reunite the Oceanic 6 for a return to the island (carrying Locke's body with them) to save the remaining survivors, while those survivors feel the effects of the island's move. Later, they come under attack by unknown forces. Meanwhile, Hurley and Sayid are on the run from police; and Kate gets some shocking advice from an old friend to ensure that "the lie" remains safe. Ana Lucia: Michelle Rodriguez. David Reyes: Cheech Marin. Carmen Reyes: Lillian Hurst.
Locke finds out the identity of the forces who have been attacking the survivors, and Desmond searches for a woman who could be the key to helping Faraday stop the island's erratic movements through time.
Kate discovers that someone knows the identity of Aaron's parents. On the island, the dramatic shifts through time place the remaining survivors in extreme peril.
Locke takes it upon himself to stop the island's increasingly violent shifts through time. Meanwhile, Ben hits a snag in his attempt to reunite the Oceanic 6 and bring them back to the island. Eloise Hawking: Fionnula Flanagan. Christian Shephard: John Terry. Ji Yeon: Jaymie Kim.
The Oceanic 6 learn how they'll be able to return to the island, but not all of them want to make the journey. Eloise Hawking: Fionnula Flanagan.
Locke (as Jeremy Bentham) takes a fateful mission off the island. Walt: Malcolm David Kelley. Matthew Abaddon: Lance Reddick.
Sawyer and other island survivors perpetuate a lie to protect themselves from mistakes of the past.
When old friends drop in unannounced, Sawyer must perpetuate his lie to protect them. Christian Shephard: John Terry. Dr. Marvin Candle: Francois Chau. Frank Lapidus: Jeff Fahey.
One of the survivors goes rogue and acts alone, risking the lives of everyone on the island. Roger Linus: Jon Gries. Young Ben: Sterling Beaumon. Young Sayid: Anthony Keyvan.
Kate tries to save Ben's life---and takes drastic measures to do so---when Jack refuses to help. Meanwhile, Kate begins to tell the truth about the lie in order to protect Aaron. Cassidy: Kim Dickens.
Ben needs to atone for his past sins, so he summons the smoke monster to pass judgment on him. He also reconnects with the risen Locke and has an encounter with Penny Widmore. Meanwhile, flashbacks trace Ben's history with Charles Widmore; and Ilana (Zuleikha Robinson) takes charge of the Ajira-flight survivors.
Ben is abducted from the infirmary, arousing concern that hostiles have gotten into the Dharma village again. Meanwhile, Hurley and a reluctant Miles team up to deliver a package to a Dharma bigwig. Naomi: Marsha Thomason. Young Miles: Lance Ho.
Faraday discloses what he knows about the island, beginning a time of reckoning. Eloise Hawking: Fionnula Flanagan.
Jack and Kate disagree over strategy for saving the island returnees; Locke consolidates his leadership of the Others; Sawyer and Juliet raise suspicions at the Dharma Initiative.
In the Season 5 finale, Jack runs into stiff opposition to his plan to set things right on the island, while Ben gets a tough job assignment from Locke. Flashbacks focus on Kate, Juliet and Sawyer.