LighthouseJack returns to his apartment after work. While washing up in the bathroom, he notices a scar on his lower torso that he doesn't remember. Just then, Jack's mother calls, asking whether there's been any progress in location Christian's body. Jack tells her there's no news and asks when he had his appendix taken out; she says it was when he was a child. He notices the time, 2:50pm, and races off to St. Marys Academy, a posh private school, where he's late to pick up David Shephard: his son.
Jack is watching rain fall on the lagoon outside the Temple when Dogen approaches. Dogen confirms that if Jack tried to leave, he'd be stopped, and Jack confirms that Sawyer, Kate and Jin won't be coming back. In the courtyard, Hurley and Miles are entertaining themselves with repetitive games of Tic Tac Toe. Hurley heads back inside, looking for some food, and finds Jacob waiting for him at the Spring. Apparently, someone is coming to the Island, and Jacob wants Hurley's help them find it.
At Jack's apartment, David is deliberately distancing himself from his father. His room is completely bare except for whatever gifts he's received from Jack, he walks around with his earphones in all the time, and it's clear this is his usual behaviour when he stays at Jack's apartment. Despite Jack's attempts to connect, David just wants to "get through" the visit. Jack's mother calls, wanting him to come over and help sort through Christian's files. David prefers to stay at home alone.
At the Temple, Sayid wonders why everyone is staring at him, but Jack says to just ignore them. Sayid wants to know what's going on with "the Sickness" and the Others' cure. Jack admits that the pill was poison, and alludes to Claire's "infection". In the jungle, Claire makes sure that Justin the Other is still alive before freeing Jin from the bear trap. She says she's been out in the jungle for the past three years, ever since the rest of the Oceanic 815 survivors left. Jin's ankle is badly injured and as soon as he tries to walk, he passes out. In the Temple catacombs, Hurley is following the instructions from Jacob (which he wrote on his arm) and looking for a section of wall with a particular hieroglyphic on it. Dogen interrupts and demands that Hurley go to the courtyard, but Jacob appears and tells Hurley what to say:
Hurley: I'm a Candidate, and I can do what I want.Dogen backs down and leaves. Jacob asks why Hurley is leaving through the secret passageway on his own: he's supposed to bring Jack along. Hurley asks how he's supposed to convince Jack to come along, and Jacob just smiles. Later, Jack is sitting in the courtyard when Hurley comes over and tries to convince him to come along.
Jack: I'm not going anywhere, Hurley.
Hurley: I told him you'd say that, so he told me to tell you "You have what it takes."
Jack: [agitated] What'd you just say?
Hurley: He said you have what it takes. He said you'd know what that meant.Jack demands to see Jacob, and when Hurley says they can find him where they're going, Jack agrees to go. Jin wakes up and finds himself in Claire's hut, which is filled with dynamite, medical supplies and, in a place of pride, a cradle that holds a fake "baby" cobbled together from bones of different animals. Claire returns, holding Justin at gunpoint, and ties him to a wooden pole. She starts asking him questions about where the Others are keeping her son, Aaron, while tending to Jin's injured ankle. When Claire leaves to go get supplies, Justin begs for Jin to set them free, claiming that Claire will kill them both. In the jungle, Jack and Hurley are hiking alongside a river, having escaped the Temple. They run across Kate refilling her canteen, and she finally tells Jack that she returned to the Island in order to find Claire, and as such she won't be going back to the Temple. Jack fills her in Claire's supposed "Sickness" but Kate insists on going off by herself. Hurley reminds him of Jacob's clear instructions that only the two of them can go where they're going.
Jack and his mother are searching through Christian's files for his will. She asks about David, commenting on how David is being uncommunicative in the same way Jack was when he was young. Jack says he didn't talk to Christian because he was terrified of his father. Just then, Jack's mother finally locates the will and starts reading it, only to immediately stop and ask who Claire Littleton is.
In the jungle, Claire is outside her hut, preparing medical tools and sharpening a huge axe. Inside, Justin asks Jin to free him, claiming that Claire will kill them both. Claire comes in and starts treating Jin's leg wound, at the same time talking about her experiences on the Island. Justin reiterates that the Others don't have Aaron and don't know where he is, but Claire isn't listening.
Jin: Claire, how do you know they took him? How can you be so sure?
Claire: How can I be so sure? Well, first my father told me, and then my friend told me, so I'm pretty damn sure.Once she's done fixing Jin, Claire picks up the axe and tells Justin that it's his turn. Elsewhere, Hurley and Jack continue hiking through the jungle and briefly discuss why he and Kate never got their relationship going right. They stop when Jack steps on something: Shannon's asthma inhaler. Jack realizes they're back at the caves. He and Hurley have a look inside and find the Adam and Eve skeletons: Hurley wonders if the skeletons could be those of two Losties who went back in time and died in the past. Jack isn't listening, because he's seen his father's coffin.
Jack: Did I tell you how I found this place? [...] I was chasing the ghost of my dead father. [''laughs''] He led me here. That was his coffin, before I smashed it to pieces.
Hurley: Why'd you do that?
Jack: Because he wasn't in it.
Jack returns home with a pizza and finds that David has gone. When he won't pick up his cellphone, Jack goes to David's mother's house (she's out of town), gets in using the spare key and looks in David's room for clues as to where he might be. The room is messy and lived in, but there's also a keyboard, books and books of sheet music and an answering machine message confirming that David has a "slot" at the Williams Conservatory that night.
Jack and Hurley are still hiking, and the topic of conversation turns to why they both returned to the Island.
Hurley: Back in LA, Jacob hopped into the back of my cab, and told me I was supposed to, so I came.
Jack: I came back here because I was broken. And I was stupid enough to think this place could fix me.They continue on, and finally reach their destination: a huge stone lighthouse on the Island's coast. At Claire's hut, she keeps questioning Justin about Aaron's whereabouts and refusing to believe that he's not with them. Jin tries to stop her doing anything rash, but Claire shows him the brand the Others gave her and tells him about escaping the Temple. As Claire is about to kill Justin with the axe, Jin reveals that Kate took Aaron when she left the Island, and Justin tries to explain—again—that the Others had nothing to do with what happened to Aaron. Claire kills him with the axe anyway and leaves the tent. At the Lighthouse, Hurley and Jack force the door open and start climbing the stairs.
Jack goes to the Williams Conservatory and learns that David is there auditioning for admittance to the selective musical school. What's more, David can play the piano. Really, really well. A young boy says as much to Jack before rejoining his own father: Dogen, who remarks to Jack that their sons are too young to be under such pressure. When asked how long David has been playing, Jack admits he has no idea.
Jack and Hurley reach the top of the Lighthouse and don't find Jacob waiting, which angers Jack. Hurley starts to carry out Jacob's final instruction: turning the Lighthouse mirror to 108 degrees, using a pulley system and a big dial with markings. As the mirror turns, Jack notices that every degree on the dial has a name written next to it, almost all of them crossed out. Furthermore, when the mirror passes a different degrees, different images appear in it: first an Asian temple (the one where Sun and Jin were married), then a church (the one where Sawyer's parents' funeral was held). He examines the dial closely and finds familiar names like "KWON", "JARRAH", and eventually his own, "SHEPHARD", next to the 23rd degree. Beginning to understand, Jack aligns the mirror to 23 degrees and a new image appears.
Hurley: What is it?
Jack: It's my house. It's the house I grew up in. [...] Haven't lived in that house since I was a kid. He's been watching. The whole time. All of us. He's been watching us.With Jacob not there and Hurley unable to explain why they've been spied on their whole lives, Jack snaps, grabs a nearby telescope and smashes the Lighthouse mirror into shards.
When David finally comes out of the Conservatory, Jack is waiting, ready to tell his son how great he played.
Jack: I didn't know you were still playing.
David: I made Mom promise not to tell you.
David: It was always such a big deal to you. You used to sit and watch me practice. You were so into it. I didn't tell you I was coming here because... I didn't want you to see me fail.
Jack: You know, when I was your age, my father didn't want to see me fail either. He used to say to me that... he said that I didn't have what it takes. I spent my whole life carrying that around with me. I don't ever want you to feel that way. I will always love you, no matter what you do. In my eyes, you can never fail. I just wanna be a part of your life.
Outside the Lighthouse, Jack is sitting alone by the edge of the cliff, staring out into the ocean, and is ignorant when Jacob finally appears to Hurley, completely cool about the mirror being broken. So cool, in fact, that Hurley realizes Jacob's plan all along was for Jack to come and see what was in the mirror.
Jacob: Jack is here because he has to do something. He can't be told what that is. He's got to find it himself. Sometimes you can just hop in the back of someone's cab and tell them what they're supposed to do. Other times, you have to let them look out at the ocean for a while.When Hurley asks why it was necessary that both he and Jack both come all the way out to the Lighthouse, Jacob reveals that it was as much about getting them both out of the Temple, because "someone bad" is going there. Hurley wants to warn everyone, but Jacob says it's too late. At Claire's hut, Jin claims he was lying about Kate having raised Aaron in order to save Justin's life, and that the Others really do have Aaron at the Temple. Claire is glad, and tells him that if Kate really was raising Aaron, she'd have to kill her. That's when Claire's "friend" arrives: the Man in Black.