"LA X" comprises the 104th and 105th episodes of the American Broadcasting Company's Lost, marking the premiere of the sixth and final season.

The first timeline begins on Oceanic Flight 815, in which the survivors' attempt to change the future has apparently averted the crash.

Marshal Edward Mars (Fredric Lehne); Dr. Jack Shephard (Matthew Fox) is transporting his deceased father; and John Locke (Terry O'Quinn) is still paralyzed.

Boone Carlyle (Ian Somerhalder) is returning to Los Angeles without his stepsister; Hugo "Hurley" Reyes (Jorge Garcia) claims to be the luckiest man alive; Locke claims to have participated in his walkabout; Desmond Hume (Henry Ian Cusick) is a passenger and Rose Henderson (L. Scott Caldwell) reassures Jack while experiencing turbulence.

During the flight, Jack is called upon to save Charlie Pace (Dominic Monaghan), who has asphyxiated while attempting to swallow a packet of heroin.

At LAX, Charlie is arrested for drug possession, and Jack learns that the airline has lost his father's coffin.

Jin-Soo Kwon (Daniel Dae Kim) is detained after failing to declare a large amount of cash on his customs form.

Jack, Kate, Hurley, Sayid, Jin, Juliet Burke (Elizabeth Mitchell), James "Sawyer" Ford (Josh Holloway), and Miles Straume (Ken Leung) have been returned to the present at the site of the Dharma Initiative Swan station, after Ben Linus (Michael Emerson) has killed Jacob (Mark Pellegrino).

At the temple, the group encounters the remaining members of the Others who have taken refuge, including Flight 815 stewardess Cindy (Kimberley Joseph) and the two abducted children, Zack and Emma, who have been missing since they were taken in by the Others.

The survivors are captured and brought before two men, the Japanese man Dogen (Hiroyuki Sanada) and his translator Lennon (John Hawkes).

Inside is a wooden ankh, which Dogen breaks open, revealing a note that tells the Others they will all be in trouble if Sayid dies.

Greg Grunberg recorded lines in Los Angeles for a voice-over reprisal of his role of Oceanic Airlines Captain Seth Norris of Flight 815 that crashed on the island in the pilot episode.

According to Lindelof, who is apprehensive that the audience will not understand or reject it, "the show demands constant shifts to best tell the story.

"[12] Lindelof has commented that the sixth season will most resemble the first for the show, even including characters sparsely seen since, saying, "We want the show to feel like a loop is closing with this final year", to which Carlton Cuse added that when the characters in the first season "were running around the jungle, things felt intense and surprising.

"[15] For years, Lindelof and Cuse have responded to theories about the greater meaning and answers of the show by pointing out that viewers did not have adequate information to theorize well.

"[16] Confronted that the bomb detonating would force a timeline change and thus render the past five seasons pointless, Damon Lindelof responded with "Trust us.

Postulating alternative realities would be an escape valve that would be damaging that as a narrative value … Carlton and I are PRO time-space continuum bending!

"[19] As the third season was wrapping production in May 2007, Damon Lindelof and Carlton Cuse negotiated with ABC for the show to end in three years.

"[24] In September, ABC Entertainment president Stephen McPherson advertised that the final season would be the first Lost season to run uninterrupted and entirely repeat-free;[25] however, Cuse said in October that Lost would premiere in January in order to take a two-week break in February to avoid competing with NBC's coverage of the Vancouver Winter Olympic Games.

[36] On January 8, White House press secretary Robert Gibbs announced "I don't foresee a scenario in which millions of people who hope to finally get some conclusion with Lost are preempted by the president",[37] to which Damon Lindelof responded via his Twitter account with "OBAMA BACKED DOWN!!!!

[38] Ben East of the United Arab Emirates The National newspaper summed up the story with "confirmation of just how important [Lost] is came with an almost unbelievable communiqué from the White House last week … That's right.

Obama might have had vital information to impart upon the American people about health care, the war in Afghanistan, the financial crisis—things that, you know, might affect real lives.

[41] Chris Carbot of IGN gave the episode a strong positive review, stating that "season six is off to a fantastic start", although he criticized the first hour of the premiere for its pacing and lack of "information that needs to be imparted to the audience."

"[44] Maureen Ryan of Chicago Tribune gave the episode a perfect score, stating "This was a fantastic season premiere.

[46] Ben Rawson-Jones of Digital Spy gave the episode four out of five stars, explaining that "the skilful hands who craft that show assembled everything so intricately that we were treated to a thoroughly compelling adventure … On this evidence, Lost will go out on a high".

Rawson-Jones commended Terry O'Quinn's dual-role performance, but lamented the treatment of Juliet's death, assessing it as melodramatic and predictable and calling it "the only real sore point of the generally brilliant season premiere.