Hurley picks up Charlie to play in the concert. Juliet checks in on Sun and her baby. During the ultrasound Jin and Sun get their memories back. It was actually quite touching the sequence of them getting their memories.
Dr. Jack promises to fix Locke. Juliet is David's mom and Jack's ex-wife. SQUEE!
Sayid tries to get answers, but Hurley refuses to tell him. He does however insist that Sayid is a good guy no matter what anyone else says about him. A fight breaks out while Hurley and Sayid wait in the car on which Hurley cryptically comments on. When the man starts to beat a young girl, Sayid jumps out of the car to save her. Her being Shannon. Boone was also there and in on it with Hurley.
Everyone gathers for the concert. Juliet gets called away by the hospital. Claire and David continue in. Charlotte wakes up Charlie and then meets Farraday/Widmore. David and Claire get to their table where Desmond and Kate - to Claire's surprise - is already seated.
Dr. Pierre Chang kicks off the concert introducing Daniel Widmore/Farraday and Drive Shaft. Daniel begins to play and Charlie spots Claire in the audience. They exchange a meaningful look. Then Claire has a contraction and gets up to go to the bathroom and Kate follows.
Eloise sits down next to Desmond who tells her he ignored her advice on leaving them alone and that when they all know they're leaving. She looks at Daniel heartstricken as she asks Desmond if he's taking her son and he says not with him.
Backstage Claire goes into labor and Kate delivers Aaron - hey! Just like in Season 1. Clever those guys. And as Claire pushes, Kate gets her knowledge of her Island life back. Claire gets her knowledge back at the sight of Aaron. Charlie brings her a blanket. When Claire grabs his hand, he gets his knowledge back. Desmond asks if Kate understands. she asks now what.
The nick on Jack's neck is back only we know what it's from. When MIB/UnLocke/Smokey held a knife to his throat. See On the Island.
Locke's surgery goes well. He starts to come out of the anesthesia quicker than is expected. Locke claims to be able to feel his legs. He wiggles his toes and receives his Island knowledge. When he asks Jack if he saw it, Jack doesn't know what he's talking about. Locke invokes a little bit of Jack's Island knowledge only he refuses to remember.
Sawyer meets Jin and Sun and tries to insert his detectiveness to protect them. They smile knowingly at him and joke at the word detective. They walk out with a we'll see you there over their shoulders. Sawyer's confused.
After running into Jack and asking for a tip on where to get food, Sawyer tries to get candy out of the machine only it gets stuck. Juliet gives him a tip to get the candy out by unplugging the machine. They get their respective Island knowledges when their hands touch. Then we get the source of Juliet talking about going dutch on coffee from the premiere. And they promptly make out.
Jack comes late to the concert where he runs into Kate. He seems to remember her. She mentions Oceanic Flight 815, and he looks freaked at the coincidence. She touches his face, and he get flashes of the Island.
Locke gets out of a cab and still in a wheelchair, finds Ben waiting outside the church where everyone is gathering. Ben apologizes to Locke for everything he did to him. Because he was selfish and wanted everything he had. Because Locke was special. Locke forgives Ben. Ben decides to stay and declares that Locke doesn't need the chair any longer. He pops up out of the chair and walks up the stairs.
Hurley comes out and he and Ben have a good moment where they recognize each other from their Island selfs as a great Number 1 and Number 2. Ben again insists that he's staying.
Jack and Kate pull up to the church. She tells him to go around the back and she'll meet him inside. He goes in to find his dad's coffin. When he touches it, he gets his Island knowledge. He opens the coffin to find it empty. And his dad addresses him from behind. Christian tells him that he's dead and confirms that Jack is dead to. Yet they're real. That together, he and the other Losties made this church so that they could find each other. And when they did, they could move on together. Christian goes on to tell him that the time he spent with them during their Island adventure was the most important time of his life. That he couldn't have done it alone. That no one can. He needed all of them, just like they needed him. Father and son hug. All the drama between them forgiven and forgotten.
Jack walks out to the Island Reunion. Everyone couples up: Jack and Kate, Sawyer and Juliet, Hurley and Libby, Charlie and Claire, Desmond and Penny, Sun and Jin, Sayid and Shannon, Bernard and Rose. And as Christian walks out the church doors, a great light fills the room. Everyone looks happy, and they move on.
On the Island
Protector Jack, Kate and Hurley go off to find the Heart of the Island while Sawyer goes off to get Desmond. Only Sawyer finds MIB/UnLocke/Smokey and Ben at the well and no Desmond. He cryptically informs MIB/UnLocke/Smokey that they are no longer candidates before he beats Ben and takes his gun and stalks back off into the jungle to meet back up with Protector Jack, Hurley and Kate.
Rose and Bernard rescued Desmond from the well. MIB/UnLocke/Smokey threatens their lives unless Desmond helps him. Desmond agrees. Ben's still got the other half of the walkie talkie he gave Miles. So he did not turncoat again. He's just waiting for his opportunity. Richard is still alive after the Smokey attack from the last episode.
Protector Jack informs Sawyer that it doesn't matter that Desmond wasn't there. They're all going to the same place and then it will be The End.
Richard starts aging meaning he's no longer immortal. Lapidus somehow survived the blast on the submarine. Miles and Richard pull him into their boat. Lapidus offers to fly them off the Island to keep MIB/UnLocke/Smokey from getting off the Island.
Jack and MIB/UnLocke/Smokey have a face off where Jack informs him that he will kill him when they get to the Heart of the Island. When they get to the Heart, they start to tie Desmond to a tree. Desmond gives Jack his pitch about the Sideways and tries to get him to go with him. Only Jack's not buying. He says that there are no shortcuts. That what happened, happened.
Miles, Lapidus and Richard show up at the plane. They finally reach Ben on the walkie and just as they're explaining to him how they're going to fly the plane off the Island, Claire comes walking out of the jungle shooting at them. Richard asks her to come with them, but she refuses.
Protector Jack and MIB/UnLocke/Smokey lower Desmond down into the Light. MIB/UnLocke/Smokey tries to bring up old memories about the Hatch only Jack dismisses his attempt at light conversation by saying he's not John Locke and that MIB/UnLocke/Smokey is disrespecting his memory by looking like him. Jack comments that Locke was right about almost everything and wishes that he could have told him that. MIB/UnLocke/Smokey says he wasn't.
Down in the Heart, Desmond sees at least two skeletons and a pool that is the source of the Light. He steps into the pool and the Light starts to flicker and make quaking sounds. He grabs the stone in the middle and pulls it to one side. The pool drains and the Light goes out. And then steam erupts from the drain and the earth quakes. MIB/UnLocke/Smokey comments that Jack was wrong and walks out of the cavern. Jack tackles him and starts to beat him. And to MIB/UnLocke/Smokey's dismay, he bleeds. Turns out he was wrong too. He smashes Jack with a rock. After a while he gets up and goes back into the cavern for Desmond but can't find him. He takes off after MIB/UnLocke/Smokey.
In the earth quake, Ben gets trapped by a tree. Sawyer, Kate and Hurley try to move the tree but get knocked around by the earth quake. Miles calls and tells them they're taking off in an hour. Ben informs them that the fastest way over there is in MIB/UnLocke/Smokey's boat.
As MIB/UnLocke/Smokey starts down the ladder to his boat, Jack calls to him. They fight it out in the rain on slippery wet rocks. MIB/UnLocke/Smokey stabs Jack. Kate shoots MIB/UnLocke/Smokey. Jacks kicks him off the cliff. He lies dead sprawled on the cliff below. Back likely broken again.
With MIB/UnLocke/Smokey, Kate declares it over. Only the earth is still quaking. Jack volunteers to go plug up the pool again. He tells the others to get on the boat and get on the plane in case he can't fix it. Ben declares that he's going to stay and go down with the Island if he must. Hurley also says he's staying. Jack insists Kate go back and get Claire on the plane. They kiss almost swallowing each others' faces and declare their love for each other. Then Jack, Hurley and Ben walk off back to the Heart of the Island.
Miles and Richard fix the mechanics in the plane. Scared they're going to miss takeoff, Sawyer and Kate jump off the cliff to get to the boat faster.
Jack, Hurley and Ben arrive at the cavern and Jack insists on going down there alone even though he won't make it. Hurley refuses to let him because he doesn't want Jack to die because he's supposed to protect the Island. But Jack insists that he is protecting the Island. That this is what he was meant to do. That he was meant only to be the Protector long enough to start up the Heart again. That Hurley is meant to be the Protector. Hurley refuses to believe it. But Jack insists and Hurley grudgingly agrees. Ben looks heartbroken. Jack gives Hurley a drink from a bottle and now they're the same.
Jack finds Desmond on the side of the pool who is shocked to realize it didn't work. That he's still on the Island. That Jack was right. Jack jokes "There's always a first time." Jack ties him to the end of the rope so Hurley and Ben can pull him up. Jack insists he goes back to Penny and little Charlie. When Desmond asks what about Jack, he replies "I'll see you in another life brutha."
They get the plane working just as Kate and Sawyer arrive on the beach to find Claire by herself upset and not wanting Aaron to see her crazy. Kate offers to help her and they all run to the plane and make it to final boarding just in time. To everyone's relief, the plane makes it off the Island.
Jack manages to get the plug back in the hole and the water starts to run while the Light starts to pulse again. Ben and Hurley pull up Desmond thinking it's Jack. Hurley is upset over the loss of Jack and his lack of knowing what to do next. Ben comforts him and reminds him that he should do what he does best: help people. Maybe by starting with Desmond and helping him get back to Penny. He theorizes that though Jacob wouldn't let anyone leave the Island, that is not the way Hurley has to do it. Maybe there's another way to run things. Hurley asks for Ben's help, and Ben looks relieved to finally be included and let in on the inner circle.
Jack wakes up in a lagoon and stumbles through the jungle to lie down in the spot he woke up in in the pilot episode. And like in the pilot, Vincent finds him. He watches the Aljira plane fly over him. And then he dies.