My LOST alternate ending:
Keep everything pre-finale the same.
Desmond’s work “awakening” people in the sideways timeline comes to a climax with him assembling everyone at the church (or at the pendulum room from when the Oceanic 6 were looking to get back to the island). Jack is there, and has his moment with Kate outside, but refuses to join the others, saying "For so long all I wanted was to go back to the island, but somehow I feel that isn’t my destiny, that I’m not supposed to go with you, but remain here, with my son.” Kate tells him she understands, and joins the others inside. Faraday is there, with his mom. He says that he cannot go with them all, but has figured out how to initiate the “transfer”. Desmond tells him he understands, and wishes him a lifetime of happiness with Charlotte. Faraday’s mom thanks Desmond for allowing her son to stay. Switches are thrown, weird shit lights up and Desmond pulls everyone in tight around him.
Back on the island, Desmond pulls the cork. The light begins to flash, the water recedes, the ominous rumblings and evil red glow appear in the cave. There is a brilliant flash of white light and…cave Desmond is gone. Outside there is a flash of white light and the focus changes from character to character as they react to the blinding light and loud humming noise (very similar to the earlier Desmond incident when he blew up the Swan site). Each character is shown winking out of existence after reacting to the light, except for Smokey/Locke and Jack inside the cave.
Smokey/Locke and Jack begin to fight, much as they did on the cliff face in the finale, only inside the cave and eventually down in the cork room. Locke stabs Jack, then leaves him for dead as he starts to climb out of the cork room. Jack sees one of the skeletons in the cork room has the same ceremonial knife used in previous episodes to attempt to kill Jacob and Man-in-Black (and that did kill their “mom”), and he grabs it and plunges it into Smokey/Locke, who at that moment comes to realize that without the power of the island he is indeed mortal. With his dying gasp Smokey/Locke says “It doesn’t matter Jack, I still win.”, then promptly begins to convulse, wavering back and forth between corporeal form and smoke form. Jack knows he’s dying, and has to do something, so he plugs the cork back in, the light and water return, there is another loud noise and white flash, and Jack is gone. Smokey finishes his transformation back into pure smoke form and lets out an inhuman howl of rage upon realizing he’s once again trapped in the glowy cave.
Cut to outside the cave where everyone from the sideways timeline appeared after the white light flash. They all see the second white flash, and hear Smokey’s howl of rage. Suddenly, the whispers start up and the glow from the cave becomes brighter. From the cave entrance emerge Michael, Ben’s daughter Alex, the Japanese guy from the Temple, and dozens of other people who lived and died on the island. Michael explains that with the evil once again contained, the spirits are now free to move on, and he thanks everyone. He apologizes to Hurley, who forgives him and says “It’s OK dude, I have her back now.”, as sideways Libby is standing with him. Sideways Sawyer asks “what the hell just happened” and Michael says “there’s someone else who can explain better than I can”. From the cave entrance comes Christian Shepard, who proceeds to explain that the explosion in 1977 created a tangent timeline that was never meant to exist. It was a manifestation of what was wrong with the island, and that the island is a force for good that protects the world from great evil. Jacob and the Man in Black upset that balance with their actions long ago, and the island has been trying to right that imbalance ever since. The return of all the LOSTies to the island has rewoven the tangent timeline back into the proper one, and restored the balance. This allowed Smokey/Locke to be defeated and imprisoned once more, and for that the island is very grateful. Christian then says the island has one last favor to ask of them, it needs a new Guardian. “Jack!” shouts Hurley, “Jack is still in there! We have to save him!” Christian says “No Hugo, Jack is where he is supposed to be. It must be another.” “From the back of the crowd comes a voice, “I will do it.”. The camera pans and it’s Ben. Christian smiles and nods, as if he’s known all along what the outcome would be.
Suddenly Ben’s radio(on the ground now) crackles to life again. It’s Miles. He, Richard and Lapidus have the plane prepped and ready and were worried that the flashes of light meant something bad had befallen the others… Sawyer tells them to hold on, and prepare for a few more passengers than they originally expected. Ben prepares to leave with Christian, and makes his goodbyes, including apologizing to Locke who forgives him. We see a montage of LOSTies boarding the plane happy and reunited with one another (much like the church scene in the finale). The music swells as Lapidus announces takeoff and the jet clears the edge of the jungle. The camera cuts to the exact same scene of Jack from the finale. He gets up from the riverbank, makes his way to the clearing where the show began, and dies with Vincent by his side. The last image he sees is the plane, now full of LOSTies, flying overhead, and he smiles.
L O S T