'''Season 5, Episode 1:'''
!Because You Left
[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/lostbecauseyouleft.jpg]]
[[caption-width-right:350:Locke is reunited with an old hunting partner.]]
->Written by Damon Lindelof and Carlton Cuse.
->Directed by Stephen Williams.

->'''Daniel:''' The Island... think of the Island like a record spinning on a turntable... only now, that record is skipping. Whatever Ben Linus did down at the Orchid station... I think... it may have... dislodged us.
->'''Miles:''' Dislodged us from what?
->'''Daniel:''' Time.

In the 1970s, the DHARMA Initiative are building the Orchid Station. Dr. Chang, the man from their orientation videos, tells them to stop their work before they risk releasing an almost limitless energy, capable of manipulating time. As the construction foreman scoffs at the notion of TimeTravel, Daniel Faraday looks on uneasily at the situation.

On the Island, the remaining survivors, along with the freighter science team and Juliet, start randomly jumping through time as a result of Ben turning the wheel at the Orchid. Locke gets shot by Ethan, but Richard appears out of nowhere and saves him, telling him that he has to get the Oceanic Six to return to the Island to save everyone, and that to accomplish this, he will have to die. Charlotte starts suffering from a strange nosebleed, concerning Daniel. Daniel finds Desmond in the past, and tells him to go to Oxford and find his mother to help them.

Off the Island, Jack and Ben discuss how they will convince the others to return to the Island with them. Kate is visited a lawyer named Dan Norton, who demands a blood sample to test her relationship to Aaron. Kate goes on the run with Aaron. Hurley and Sayid are also on the run, wanted for the murder of the man stationed outside Santa Rosa whom Sayid killed. They encounter another group of assassins at their safe house. Sayid kills them too, but is knocked out by an anaesthetic dart in the process, forcing Hurley to rescue him. Sun proposes an alliance to Widmore to kill Ben. Desmond suddenly awakes with the memory of Daniel's message, and he and Penny set sail for Oxford.

!Tropes in this episode include:

* AccidentalTimeTravel: Ben turning the Frozen Donkey Wheel has inadvertently caused the freighter team, the Oceanic 815 survivors, and Juliet to start randomly flashing through time.
* AnswerCut:
** Ben tells Jack that they'll probably never know what happened to the people who were left behind after the Island moved. The next scene flashes back three years and shows us exactly that.
** When Daniel says that they can't stop the time flashes, and Sawyer asks who can, we immediately cut to Locke.
* ArcWords: The phrase "whatever happened, happened", which will be an important theme of the season, is said for the first time in this episode.
* BetterManhandleTheMurderWeapon: After Sayid kills one of the assassins looking for him, Hurley impulsively grabs the dead man's gun. He's practically posing for the camera phones of the bystanders who come across the corpse.
* CallForward:
** Dr. Chang records the DHARMA orientation video for the Arrow, and visits the Orchid while it is under construction.
** Locke witnesses the beechcraft crashing on the Island.
* ComicallyMissingThePoint: Locke mistakenly believes that the compass Richard gives him has some magic properties.
-->'''Locke:''' What does it do?
-->'''Richard:''' [[AskAStupidQuestion It points north, John.]]
* ContinuityNod: The ColdOpen showing Pierre Chang going through his MorningRoutine is staged similarly to the opening scene of "[[Recap/LostS02E01ManOfScienceManOfFaith Man of Science, Man of Faith]]" that followed Desmond through his own routine.
* ContinuitySnarl: Ethan didn't show any signs of recognising Locke when they hunted together in Season 1, despite meeting him while time-travelling here.
* DeadlyNosebleed: Charlotte starts to develop one of these, similarly to Minkowski and Desmond in "[[Recap/LostS04E05TheConstant The Constant]]", much to Daniel's alarm.
* DelayedRippleEffect: It's implied that Daniel changes Desmond's past in giving him a message at the Swan, which is why he suddenly gets a new memory of their meeting after he's already left the Island. However, for some reason, Desmond remembers this three years later, rather than immediately after the time flashes started.
* DramaticIrony: A DHARMA Initiative worker at the Orchid dismisses Dr. Chang's talk of time travel as ridiculous, unaware that he's talking to Daniel Faraday, a time traveller from 30 years in the future.
* EmergencyTemporalShift: An unintentional example. A time flash saves Locke when he's about to be shot by Ethan by moving him into the future.
* EnemyMine: Implied with Sun and Widmore seemingly teaming up to kill Ben.
* FlingALightIntoTheFuture: Unable to stop the time flashes, Daniel gives a message to Desmond in the past so that he will remember it after he gets off the Island and contact his mother to help.
* FreudianSlip: When Juliet asks Sawyer why he jumped off the helicopter, he says he wanted to make sure she... they made it to the freighter.
* {{Futureshadowing}}: We see the aftermath of Locke's attempts to convince the Oceanic Six to return to the Island before we see the mission itself.
* GivenNameReveal: "Dr. Marvin Candle" from the DHARMA Orientation videos appears in the opening scene, and it's revealed that his real name is Dr. Chang.
* HaveWeMetYet:
** Downplayed when Daniel encounters a pre-Oceanic crash Desmond, who seems to vaguely recognise him from their encounter in 1996 in "[[Recap/LostS04E05TheConstant The Constant]]", but still doesn't know him as well as he will after the freighter arrives.
** Ethan is very surprised when Locke already knows who he is, and is even more confused when Locke says that Ben made him the leader of the Others.
** Discussed when Richard warns Locke that he won't recognise him the next time they see each other.
* HisNameIs: Daniel tells Desmond to find his mother to help stop the time flashes, but is interrupted by another flash before he can tell him her name.
* HitlersTimeTravelExemptionAct: Discussed. Dr. Chang dismisses the idea out of hand.
-->'''Foreman:''' Right. Okay, so, what? We're gonna go back and kill Hitler?
-->'''Chang:''' Don't be absurd. There are rules, rules that can't be broken.
* HowWeGotHere: The season opens with a scene of Daniel Faraday observing the building of the Orchid Station, introducing the theme of time travel. It's not until much later in the season that this scene is revisted.
* ImportantHaircut: Downplayed. Jack shaves off his BeardOfSorrow, but it's clear that he still has a long way to go before he's back to his old self, and his new appearance is not an instant fix.
* ImprovisedWeapon: Sayid kills a hitman at the safe house by throwing him onto an upturned knife in the open dishwasher.
* InstantSedation: Averted; Sayid takes several tranquilizer darts but takes a while to go down.
* MrExposition: Daniel gets to explain to the rest of the characters, and the audience, exactly how time travel works.
* ScrewThisImOuttaHere: Sawyer decides he's not going to start over with basic survival and intends to spend time in the Hatch.
* SetRightWhatOnceWentWrong: Defied. Sawyer and Juliet consider trying to use the time flashes to their advantage, by warning their friends not to go back to the freighter before it blows up, but Daniel tells them that this is impossible.
-->'''Daniel:''' You cannot change anything. You can't. Even if you tried to, it wouldn't work.
-->'''Sawyer:''' Why not?
-->'''Daniel:''' Time—it's like a street, all right? [[StableTimeLoop We can move forward on that street, we can move in reverse, but we cannot ever create a new street.]] [[YouCantFightFate If we try to do anything different,]] [[FailureIsTheOnlyOption we will fail every time.]] [[ArcWords Whatever happened, happened.]]
* StableTimeLoop: According to Faraday, this is how time travel works. Any attempts to change the past will fail, and anything the time travellers do will only fulfill what was meant to happen anyway. However, Desmond is an exception to this rule, as Faraday succeeds in changing his past to send a message to the future Desmond after he gets off the Island.
* TimeTravelTenseTrouble: Richard and Locke have an exchange that uses this when Richard takes the bullet out of Locke's leg, but it's not entirely clear what Richard's talking about until later in the season.
-->'''Locke:''' How did you know there was a bullet in my leg, Richard?
-->'''Richard:''' Because you told me there was, John.
-->'''Locke:''' No, no. No, I didn't.
-->'''Richard:''' Well... you will.
* TimeyWimeyBall: Although the "whatever happened, happened" rule generally remains consistent, it's never explained why Desmond is an exception to it or how Daniel's conversation with Desmond in the past suddenly gives him new memories a full three years after he left the Island.
* TitleDrop: Ben, when Jack asks him why everything's gone wrong.
-->''"It happened because you left Jack."''
* WalkingShirtlessScene: Sawyer spends the entire episode shirtless since he took his shirt off while swimming back to the beach after jumping off the helicopter, and all of the survivors' possessions were left behind in the first time flash. He's very irritated by this, since he's completely exposed to the sun, and angrily demands a shirt from Daniel, to no avail.
* WhamLine: When Locke asks Richard how he's supposed to get the Oceanic Six to return to the Island.
-->'''Richard:''' You're gonna have to die, John.
* WhamShot: Daniel Faraday appearing in a flashback to DHARMA Initiative times, right after we've heard characters discussing time travel.
* WhatYearIsThis: When Locke has his leg treated by Richard, he asks ''when'' he is.
* WouldHitAGirl: PlayedForLaughs. When Charlotte gets mad at Sawyer for hitting Daniel, he tells her to shut it, or she'll be getting one too.
* YankTheDogsChain: Locke gets to be the leader of the Others, just like he wanted... for about thirty seconds, before he's whisked away from them by a time flash and ends up getting shot and being told he's going to die.
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