"Because You Left" is the television season premiere of the American Broadcasting Company's fifth season of the serial drama television series Lost. The episode is the eighty-fourth episode of the show overall. It first aired on January 21, 2009 on ABC in the United States and was simulcast on A in Canada. "Because You Left" is the first original Lost episode to be aired on a Wednesday (in the US) since the third season. It aired immediately after a clip-show that recaps the first four seasons and aired back-to-back with the next episode, "The Lie". The episode was written by executive producers/show runners Damon Lindelof and Carlton Cuse and directed by co-executive producer Stephen Wiliams
The episode begins in the late 1970s, when the Dharma Initiative has begun to build stations on the island. Dr. Pierre Chang (François Chau) begins to film the orientation film for the Arrow Station, when he is informed of an incident at the construction site of the Orchid Station. Upon arriving there, he realizes that the workers have found the "unlimited" energy source that the Dharma Initiative has been looking for, which will enable them to manipulate time. As he leaves the station, he bumps into Daniel Faraday (Jeremy Davies), who is dressed as a Dharma construction worker.
On December 30, 2004, following the island being moved in "There's No Place Like Home", the survivors of Oceanic Flight 815, the freighter team, and Juliet Burke (Elizabeth Mitchell) begin to erratically jump through time, while the Others are unaffected. The first jump takes them to the day when the Beechcraft carrying Mr. Eko's brother crashes onto the island. John Locke is shot in the leg by Ethan Rom (William Mapother), who has not yet met him and therefore does not recognize him, while trying to help. Meanwhile, James "Sawyer" Ford (Josh Holloway), Juliet and the freighter team head to the Swan Station in order to determine when they are. A second jump brings the group forward in time to after the destruction of the station, saving Locke from Ethan in the process. When pressed for an explanation by Sawyer, Daniel Faraday likens the experience to a record skipping. Locke is approached by Richard Alpert (Nestor Carbonell), who recognizes Locke and treats his wound. He informs Locke that they will be strangers at their next meeting, and thus gives him a compass to get his younger self to trust Locke. He explains that the only way to stop the erratic movements through time is to bring back everyone who has left the island, and to do that Locke will have to die. At the Swan station, which is now intact, Sawyer attempts to make contact with Desmond Hume (Henry Ian Cusick), who he believes is inside. When no one answers and Daniel explains that the past can not be changed, everyone heads back to the beach. However, Daniel stays behind and talks to Desmond (in a hazmat suit), telling him that if Desmond's future self and the survivors of 815 made it off the island on the helicopter then he should go to Oxford University and find his mother, in order to help the survivors. Another jump occurs just before Daniel can give his mother's name.
In 2007, following Hugo "Hurley" Reyes's (Jorge Garcia) breakout of a mental institution, he and Sayid Jarrah (Naveen Andrews) go to a safehouse, which has been infiltrated by two armed men. Sayid kills the men, but not before one of them shoots him with two potent drugged darts, knocking him unconscious. In London, England, while en route to Los Angeles, Sun-Hwa Kwon (Yunjin Kim) is confronted by Charles Widmore (Alan Dale) at the airport. She tells him that she wants to kill Benjamin Linus (Michael Emerson), a desire they seem to have in common. Back in Los Angeles, two lawyers visit Kate Austen (Evangeline Lilly) and serve her with a court order for a maternity test for her and Aaron, Claire Littleton's (Emilie de Ravin) son, whom Kate is raising as her own, but they refuse to reveal their client's identity. Meanwhile, Ben and Jack Shephard (Matthew Fox) have left the funeral parlor with Locke's body. They discover that Hurley has broken out, hindering Ben's plan to reunite the Oceanic Six. On a boat in an unknown location, Desmond wakes up, having remembered what Daniel told him, and sets off for Oxford.
Following a writing "mini-camp" to map out the fifth season, the premiere's script was written and filming began on August 19. The season premiere is the first Lost episode to not only be filmed in high definition, but also edited in it.
As of "Because You Left", Emilie de Ravin and Harold Perrineau, who respectively play Claire Littleton and Michael Dawson, are no longer included in the main cast. In the fourth season, Jeremy Davies as Daniel Faraday, Ken Leung as Miles Straume and Rebecca Mader as Charlotte Lewis were credited in the main cast in the on-screen episode credits, but billed as guest stars in news releases and other media; in the fifth season, they are now billed fully in the main cast. As part of a three-year deal that began with the fourth season, writing team Edward Kitsis and Adam Horowitz now receive the executive producer title. Staff writer Brian K. Vaughan is upgraded to a producer with this season and Paul Zbyszewski and Melinda Hsu Taylor join the writing staff.
Co-creator/executive producer/head writer/show runner Damon Lindelof has stated that "When season five starts, you won't know when or where you are. And the way we tell stories will be different too." Lindelof also confirmed that the "whooshing sound" effect will continue to be used as the transition for the new storytelling device. When asked if episodes continue to focus on specific and different characters, actor Jorge Garcia, who portrays Hurley Reyes, replied that "It's not as clear cut as it's been in the past. We don't have the moments where someone stares off into space and then we cut to something that happened in their previous life. They've gone in a slightly different direction as far as how they're telling the story and they're definitely trying to show what's going on with more people in every given episode."
In regard to what Lindelof described as "the Zodiac boat with Faraday and the five people that have never spoken a line on show", executive producer/writer/show runner Carlton Cuse said that "I'd be a little bit more worried about the non-line speakers than Faraday", while Lindelof added that "things are looking up for Faraday" and "there is a monsoon coming." Regarding the background survivors in general, Carlton Cuse has responded that there is "a very tragic event that happens this season." According to Lindelof, Neil "Frogurt" (Sean Whalen), a background survivor who has appeared solely in the Lost: Missing Pieces mobisodes, "will rise up this season in the grand tradition of Dr. Arzt [Daniel Roebuck] to let his feelings be known." The character of James "Sawyer" Ford (Josh Holloway) is shirtless throughout the episode. Holloway kept fit in the summer break before shooting and noted this as "really disturbing. Coming after a hiatus, that ain't fair!"
"Because You Left" introduces a character who was named during casting as "Martha" and described as an attractive, smart and capable Asian scientist who is taking a break to raise her baby. "Dan" is a friendly yet villainous, successful attorney with a "real menace lurking below the surface".
The fifth season of Lost was promoted with a music video for the song "You Found Me" by The Fray intercut with new Lost scenes and the tagline, "Destiny Calls". Television critic Maureen Ryan of The Chicago Tribune has deemed the latter an "endlessly mockable slogan"; Don Williams of BuddyTV gave a more positive review, summing it up as "a fitting way to describe the upcoming season." The staff of TV.com ranked the fifth season first on their "Most Anticipated of Early 2009" list. Christopher Rosen of The New York Observer went so far as to deem the return of Lost a "bigge[r] event" than other happenings in that week, specifically the unveiling of the 81st Academy Awards nominations and the United States presidential inauguration of Barack Obama. "Because You Left", as well as the following episode "The Lie" averaged 11.347 million viewers in the US and 1.195 million in the UK. The episode, aired by itself, brought in 405,000 Australian viewers. "Because You Left" and "The Lie" were uploaded to ABC's media website—ABC Medianet—on December 29, 2008 to be viewed by members of the press for advance reviews attached to limited confidentiality agreements. Aggregate review website Metacritic assigned a metascore—weighted average out of 100 based on impressions of fourteen critics—of 77.
James Poniewozik of Time thought that "Because You Left" provided a good balance of characterization and mythology and commended the character of Faraday, partially "because a perfectly-cast Jeremy Davies has turned him into a likeable, flawed, brusque, slightly-in-over-his-head nebbish-god." Matt Mitovich of TV Guide stated that the premiere "offer[s] compelling twists … the foundation is laid for a pivotal penultimate season … it sends the mind reeling and uncorks infinite possibilities." Robert Bianco of USA Today wrote that "it's hard to name a series that is as engaging, surprising and flat-out gorgeous as Lost, or one in which every effort and penny expended seems to be put to shimmering good use. This is an epic big-screen adventure done for the small screen—and done in a way that makes most big-screen versions pale in comparison." Bianco also commended the characterizations, noting them as realistic and compelling. Maureen Ryan of The Chicago Tribune praised the opening sequence, calling it "really, really great … nerd-tastic for [the] hardcore Lost fan; it's full of shout-outs and callbacks to classic Lost moments and trivia." She concluded that the premiere is "quite good" (three and a half out of four stars) with "a lot to like", specifically the expanded screen time for Faraday; however, Ryan expressed difficulty in understanding the use of time (travel) in the show and felt that one to two more viewings were warranted for her to give a better review of that aspect. Verne Gay of Newsday summed up that "The season's premiere represents pig-in-the-python storytelling—there's so much to work through, so many details, stories, characters and time dimensions to attend to, that after a while this all starts to feel like a very full meal. A bloated feeling may result." Among other pieces of praise, Tim Goodman of the San Francisco Chronicle was impressed by the "parallel plotting" of the characters on and off the island in different times. Despite deeming the premiere "riveting" and the script "tantalizing as ever", Matthew Gilbert of The Boston Globe had a mixed response, for he worried that he would not be able to handle a season's worth of time travel, stating that "I may be alone in this, and I hope I will be proven wrong, but I expected the solution to "Lost" to be more metaphysical, and more original, than simply people being unstuck in time." Alan Sepinwall of The Star-Ledger deemed it "really good, in terms of keeping the momentum from last season going, servicing the characters and their emotions, and providing an appropriate number of 'Whoa's per hour." In a three out of four stars review, Thomas Connor of the Chicago Sun-Times stated that "the time-travel training wheels are coming off—and the path thus far seems blissfully free of the usual stumbling blocks", due to the previous four seasons of "baby steps" that set up the science fiction driven fifth season. Caryn Kunz of the Honolulu Advertiser said that "This was a great episode to get back into every aspect of our favorite show: relationships, mythology, reunions/cameos, and enough whoa moments to keep me on the edge of my seat throughout."
Jeff Jensen of Entertainment Weekly summed up the entirety of the premiere as "pretty cool" and "worth the wait". He wrote that "Lost's tradition of opening the year with a killer, capture-the-imagination sequence is honored and upheld, though the thing I loved most was how it was brazenly frank (and engagingly funny) about the heady high-concept conceit that will define the season." Brian Lowry of Variety concluded that "Lost … approaches its twists with what appears to be a greater degree of intellectual rigor than almost anything else on primetime. Even when it's difficult to keep track of the myriad connections, a sense lingers that somebody knows—which is strangely reassuring." Despite being more interested in the romantic aspirations of the show's characters, Jennifer Godwin of E! remarked that "the Lost mythology is a miracle to behold. It's grandiose, compelling, gaspworthy and, despite what the haters would have you believe, altogether satisfying". Katherine Nichols of the Honolulu Star-Bulletin enjoyed the opening scene, "but the rest of it didn't capture [her] as [she] hoped it would", citing high expections due to the eight-month hiatus after the fourth season finale and a possible "yearning for more character-driven stories over machinations revolving around time travel, however clever they might be." John Kubicek of BuddyTV said that "the opening scene itself will leave your mouth wide open and you'll probably forget to close it for a few minutes." He also wrote the premiere episodes "are vintage Lost, full of some unbelievable twists and a whole lot of groundwork". H.T. Strong of Ain't It Cool News said that "Because You Left" "is a corker, aggressively advancing the story in all kinds of directions."