Ok–here’s the wrap-up.
So, we’ve got the Past Losties living happily in Dharmaville in 1977. They’re joined by 5(?) of the future losties from the plane who are integrated into Dharma with help from one of the Past Losties who’s now head of security.
Oh, and Dharma, despite having worldwide operations, insane amounts of money, the resources to build underwater power stations, time-travel devices, etc is now shown as a bunch of semi-competent granola-eating hippies out to have a good time. Because the authors said so, that’s why.
One of the Past Losties meets up with 12 year old Ben (who’s dad is in Dharma) and shoots him. A different Past Lostie gets bent out of shape about this (because she’s a walking idiot-plot device. Her motivation is always to do the stupidest thing possible that will advance the plot) and takes dying L’il Ben to The Others who say they can heal him but he won’t have a soul and will be an Other. They say “Cool!”
Meanwhile, in the future Grown Up Ben (who doesn’t remember any of this) along with a few losties who didn’t go into the past and some of the remaning passengers are met by Locke, back from the dead. Wow.
He gathers them together and goes to get The Others. He then marches all of them to where Jacob (mysterious leader of The Others) lives in a secret room under the 4-toed statue.
MEANWHILE, there’s a new group. Seems that Jacob likes minions: in addition to The Others, Jacob has a second group who show up with Locke’s casket just as Locke and Ben go into the secret room under the Statue. Locke taunts Ben (“You worked all this time for Jacob and you never got to see him, he treated you like a flunky, etc”) and hands Ben a knife. Ben stabs Jacob a whole bunch of times. Locke kicks Jacob into a fire where he burns up like he was old newspaper doused in kerosene.
Meanwhile, on the beach, it turns out that Locke’s body was in the casket! He IS dead! So who’s in the room under the foot?
Locke turns into the Smoke Monster. He’s been pretending to be Locke all along, ever since the plane crashed again. He says he wants to get off the island once and for all and Jacob was stopping him.
Meanwhile, back in 1977, the losties decide to try to reboot time. They’re going to drop the atom bomb that the army was going to blow up in the '50s into the hole where the Hatch (remember the hatch?) was built–They figure “If we stop the hatch from being built, there won’t be a button for Desmond to forget to push and our plane won’t get fried.”
So they set off the nuke in the hole under where the Hatch will be.
One of them dies.
The next season opens with our heroes landing in LA…in 2004…they’re exiting the plane. Apparently the atom bomb worked–they never crashed.
Except that there’s a cut and you see the same losties wake up on the island in the crater where The Hatch used to be. It seems that the Atom bomb didn’t work–it just blew them back to their future.
At this point, everyone watching figures that “Hey! The bomb created an alternate timeline. Cool!” I’ll refer to characters in the timeline where the plane landed safely with the prefix “Alt”
So–back on the island, all the losties on the beach near where Jacob were killed make a run for a nearby temple that Jacob’s minions say will protect them from the now apparently unfettered smoke-monster.
In the process, a few of them get split off. Meanwhile, the Losties from the past get split up. Some of the losties from the past meet up with the present-day losties heading for the temple and most of them go there.
In the temple are a bunch of people who waste about 5 episodes and are all killed by the smoke monster. The only really important thing that happens is that one of the past-losties is dying from a gunshot gotten when the Dharma folks objected to them blowing up an atom bomb on their island. The boring temple people put dying guy in a magic pool. He stays dead for a while. Then he gets better. This freaks out the boring temple people who try to have Jack kill him (Jack objects) and then send him out with a knife to kill the Locke-shaped smoke monster. It fails and he joins the Smoke Monster.
The smoke monster says “I’ll kill anyone who stays in the temple, and I’ll spare anyone who comes out.” This happens.
Meanwhile, in the ALT timeline, we learn that the Island sank at some point in the past and some of the characters have changed histories (from before the plane flight). Alt-Locke has a decent relationship with his girlfriend. A conman on the island has instead become a cop. Jack has a son. Etc. Eventually Alt-Desmond meets Alt-Penny (his girlfriend…remember Penny?) and suddenly becomes aware of the real timeline (on the Island). He starts either hooking people up with their true loves or running them over with cars. Either one will make you remember.
Back on the island, Whidmore shows up with some minions. He kills a ton of the remaining people. He wants to…do…something…with the island.
The smoke monster wants to leave the island and says Jacob wasn’t letting him. Now that Jacob’s dead, all he has to do is get all of Jacob’s pre-selected potential replacements (“candidates”) together and they can all leave at once. But it’s all or nothing.
No-one trusts Smokey, so when they get to the submarine that Whidmore and his goons came in, they push Smokey into the water, get in the sub and drive off.
But wait! Smokey has put a bomb in someone’s backpack. Jack (now a faith-guy) says “He can’t kill us. It’s against the rules. Just let the timer go out.” (there’s some evidence that Jack may be right. And there ARE some ill-defined mysterious rules–so it’s not a screwball a statement as it sounds here). No one believes him and they pull the wires which makes the timer speed up. The guy who was brought back to life in the pool of water has been a semi-evil zombie up until now. Suddenly he gets better, takes the bomb and runs to one end of the sub. It blows up killing him but give the others a chance to escape. Except for one couple that has been separated since the freighter explosion and who finally got together in the last two minutes of the previous episode. She’s trapped under a convienient beam and he chooses to stay with her. So after three seasons of waiting for them to get back together, they’re together for maybe 45 minutes, tops and then killed. It turns out that Smokey can’t leave the island until all of the replacements are dead.
There’s a flashback episode where we see a shipwreck on the island in the past. A crazy lady in a cave helps a pregnant shipwrecked lady give birth to twins–as soon as the kids are born, crazy-lady beats mommy to death with a rock. One of the kids is named Jacob and the other doesn’t get a name, but we know he’ll be the smoke monster. The kids grow up and Jacob is content to stay with crazy-mommy, while pre-Smokey likes to explore. Turns out that there were more survivors of the shipwreck. Pre-Smokey tells mom “Bye toots” and goes to join them. Mommy takes Jacob to a cave filled with a bad special effect of a glowy yellow light. It’s the heart of the island, she says. (Oops–we learned earlier that the island is a cork holding back some great eee-vil. What it is? Never explained and it contradicts what mommy is about to say). Mommy says the heart of the island is all about goodness and stuff and needs to be protected but if you go into the light, you’ll suffer a fate worse than death. She scoops up a goblet full of water from the glowy stream that flows into the cave and has Jacob drink it so now he’s the protector. Mommy then kills all of pre-Smokey’s friends (how? We don’t know) and beats up pre-Smokey who’s trying to build the frozen donkey wheel.
These acts piss off pre-Smokey who kills mom. Jacob beats up pre-Smokey and pushes his body into the glowy cave, even though mommy explicity said not to. A few seconds later, out pops the smoke monster. Jacob finds his brother’s body on a rock and puts it in a cave with mommy’s body. End of flashback.
Alt-Desmond clearly has a plan in the Alt-Universe and is getting people together–waking them up one by one. The buildup of this is really well done.
On the island, the Ghost of Jacob asks the remaining losties if one of them will take over for him. Jack volunteers and drinks some water as Jacob goes away.
Meanwhile, Ben kills Whidmore and joins up with Smokey.
Desmond is captured by smokey and everyone meets at the cave entrance. Desmond (who earlier got a glimpse of the alt-timeline) goes down into the cave and there’s a big crater filled with glowy water with a stone plug in it. He pulls the plug. The water drains out. Fire and brimstone erupt.
In the alt-timeline, everyone’s remembered the Island except Alt-Jack (who’s gotten a few flashes of it but doesn’t quite remember yet).
The island starts shaking and it’s gonna explode or sink or something. Smokey makes a run for the beach–he wants to get in his boat and escape. We keep gettting told this would be catestrophic but we’re never really sure why.
Jack and Smokey have one big last fight on a cliff. Jack gets stabbed but kills Smokey (who, remember, was trapped in Locke’s body). Apparently pulling the plug on the magic water pool made the smoke-monster mortal. But the island’s still gonna explode.
Ben and one other lostie go back to the cave with Jack. The rest of the losties go back to the second plane and begin to pilot it off the dying island.
Jack gives the remaining lostie a sip of the magic water and turns the protetctorship over to him. The remaining lostie asks Ben to help him. Since Ben’s been bitter about not being allowed to help, this warms his evil, mass-murdering heart and he agrees.
Jack goes back into the cave (despite the fact that other than Desmond who’s special, no-one’s supposed to enter the cave or they get turned into a smoke monster) and first rescues desmond and then puts the cork back into the drain. The island doesn’t blow up.
Jack appears outside the cave in exactly the same place he woke up on the island in the first place and dies, right where he started.
Meanwhile, back in the Alt-Timeline, everyone gathers at a church…they just know to. Alt-Jack goes in the back entrance and sees his dad’s coffin. He opens the coffin and there’s no-one inside. Alt-Jack’s dad shows up in front of a stupid-looking, cheesy-assed stained glass window embellished with every religous symbol you can think of on it. It looks just like those stupid “COEXIST” bumper-stickers.
Turns out, sez Jack’s Dad, that this isn’t an alternate timeline after all, it’s the waiting room to heaven. Jack and dad go into the church where everyone from the first season (except those who don’t count, apparently) are waiting for him. There’s much hugging and crying, and Jack’s dad opens the front door and they all walk into the glowy, overexposed heaven together.