Here's where some of Lost's major characters found themselves at the end of last season. (Warning: Lost's oddball plots seem even stranger when you see them written down.)
Kate Austen (Evangeline Lilly)
Among a group of six survivors from the 2007 crash of Oceanic Flight 815 who left the mysterious island. She tried to return with four others on Ajira Airways Flight 316, only to be pushed back in time 30 years. Estranged from former island flame Jack Shephard, she nevertheless tried to help him set off a hydrogen bomb aimed at changing history so they would never crash.
Jack Shephard (Matthew Fox)
A flawed hero, he was flung into the past with fellow castaways Kate and Hugo "Hurley" Reyes (Jorge Garcia) while trying to return on the Ajira flight, eventually blending in with a group studying the island's properties, called the Dharma Initiative. He became convinced that a hydrogen bomb detonated in a pocket of electromagnetic energy on the island could reset time. He fought Dharma workers and his own fellow survivors to try to set off the weapon.
James "Sawyer" Ford (Josh Holloway)
Stuck on the island when six other survivors escaped (dubbed the Oceanic 6), he and several other castaways found themselves flashing through time until they stopped in the 1970s. He spent three years living among the Dharma crew under a false identity until Jack and the others appeared. Eventually, after a fight, he reluctantly helped in Jack's attempt to set off the bomb.
John Locke (Terry O'Quinn)
While trying to convince the Oceanic 6 of their need to return to the island, Locke is murdered. When most of the Oceanic 6 survivors return to the island on the Ajira flight, they transport Locke's body with them. In a twist, he returns to life on the island in the present day, determined to meet its mysterious caretaker, Jacob. But when he does, it appears that Locke is not who he once was.
Benjamin Linus (Michael Emerson)
Once the brilliant, manipulative commander of the Others, a group that killed the Dharma people, Linus was replaced by Locke as leader. Off the island, Linus kills Locke. But when Linus joins the Oceanic 6 in their return to the island, he and Locke arrive on the island in the present day. Locke eventually goads Linus into killing Jacob.
Sun-Hwa Kwon (Yunjin Kim)
Rescued from the island among the Oceanic 6 when her husband was not, Sun returned on the Ajira flight, hoping to find her spouse, Jin (Daniel Dae Kim). Instead, she landed with Locke and Linus in present day, discovering an old photo indicating Jin might be stuck 30 years in the past.
Sayid Jarrah (Naveen Andrews)
A former member of the Iraqi Republican Guard, he served as a hitman for Linus after leaving the island. Captured by a bounty hunter and put on the Ajira flight to return, he landed in the 1970s and was eventually shot while helping Jack move the hydrogen bomb.
Juliet Burke (Elizabeth Mitchell)
An Other who fell in love with Sawyer and lived with him in the '70s era Dharma camp, she eventually helped Jack set off the bomb, beating the device with a rock after accidentally falling down a mine shaft with it. But did the explosion reset time?
Jacob (Mark Pellegrino)
A mysterious being who seems to have lived on the island for hundreds of years, he has touched each of the main castaways at crucial points in their past, indicating their lives may be linked. He seems opposed by the unnamed Man in Black, who may have taken Locke's form to goad Linus into killing Jacob.
Michael Dawson (Harold Perrineau)
An original castaway who was seemingly killed in an explosion in Season 4, he is returning to the show this season, according to producers.
Elizabeth "Libby" Smith (Cynthia Watros)
A castaway who unknowingly crossed paths with Hurley and Desmond Hume (Henry Ian Cusick) before landing on the island, she was accidentally killed by Michael while he was murdering someone else to fulfill a secret deal with the Others in Season 2. She is also supposed to appear this season, according to producers.
Claire Littleton (Emilie de Ravin)
A pregnant castaway who gave birth on the island, she disappeared into the jungle in Season 4, following someone who looked like her dead father. The actor is back in the cast, but there is no information on the return of Claire, later revealed to be Jack's half-sister.