Opening with Locke waking up in hospital, Lost returns after a week’s brake with the highly anticipated and very secretive episode “The Candidate”. The flash sideways sees Locke waking after surgery following being run over by Desmond a few weeks back. As he comes to, Jack is standing beside him to tell him how the operation went. Jack also tells Locke that he is a Candidate. When Locke asks what for, he is told for a pioneering surgery that could see him walking again, but he refuses the offer.
Jack visits Bernard, who in the flash sideways is working in a nearby hospital, and asks for Locke’s notes as he wants to know how Locke was injured. Bernard reminds Jack they were on flight 815 together, then gives him the name Anthony Cooper as someone he can speak to find Locke. Jack attempts to visit Anthony Cooper but is stopped by Locke’s girlfriend who tells him to go away and leave Locke alone. Jack tells her that it isn’t enough that he saved his life, he wants to do more. She takes him inside where he finds Anthony Cooper, Locke’s dad, in a wheelchair.
Back in the hospital, Jack visits Locke again. While asleep, Locke mutters about pushing a button. Outside the room, Jack hears Claire and leaves Locke’s bedside to speak to her. Claire tells him she knows it is awkward to have just found out they are brother and sister at their father’s will but she wanted to ask him about a box her father left her. She asks if Jack knows if there is anything significant about it. Jack says he doesn’t. They realise that they were on the Oceanic flight together on the way back from Sydney and Jack asks if she wants to stay with him seeing as they are family.
In the hospital Locke is being discharged. He passes Jin in the corridor, then Jack approaches him. Jack tells him that he has been to see his father, which leads Locke to tell him that the reason he and his father were injured is because he crashed a private plane and he blames himself which is why he doesn’t want the surgery. Jack tells him that he needs to let go of the past and that he wants him to go through the surgery. Locke laughs and says he has to go. Jack tells him that he can help but Locke still leaves.
On the Island, Jack awakens on the beach with Sayid watching over him. Sayid tells him they are on Hydra Island.
Meanwhile, Sawyer and the others find themselves being led towards the cages that they once were held captive in by Ben. Sawyer refuses to go inside and snatches a gun from one of their captives, but before he can do anything Charles Widmore appears and threatens to shoot Kate. Charles tells them that Sawyer, Jin, Sun and Hugo are all safe, but he does not care if Kate lives or dies. Sawyer gives up his gun and the group are herded into the cages. Charles tells Sawyer he is doing it for their own good, obvious insinuating that he is protecting them against the Man in Black.
On the beach, the Man in Black tells Jack that Widmore has the others captive in cages and they have to save them, then they can get to the plane. Jack tells him that he isn’t leaving the Island. The Man in Black tells him that he needs Jack to convince the others to leave with him. When Jack asks why he should trust him, the Man in Black tells him because he could kill them all if he wanted to.
In the cages, Sawyer tells Kate that in the cave he saw their names hers was crossed out. Jin and Sun talk about their baby. Suddenly the power goes off leaving the camp open to the Man in Black who sweeps through the camp as the smoke monster killing Widmore’s men as he passes them. As the smoke monster departs, Jack appears and releases the group from the cage. They flee through the jungle, heading to the plane. Kate asks Jack if he is coming with them. He tells her that he is taking them to the plane but isn’t getting on it. Sayid meets them and tells them Locke is waiting for them.
The Man in Black arrives at the plane and kills Widmore’s men that are guarding it. He boards the plane and finds it wired with explosives. The group arrives at the plane and finds the bodies of Widmore’s men. The Man in Black appears on the plane steps and says he killed the men. He tells them not to worry about the men as Widmore knew what would happen to them. He says Widmore wanted them to get on the plane so they would be trapped their and could be killed easily themselves. Sawyer asks how they would be killed and the Man in Black shows him the explosives he found in the plane. He says that they can’t leave the Island on the plane so they have to leave on the submarine instead. Sawyer and Jack hang back from the group as they leave. Sawyer tells Jack that he wants him to do one last thing; make sure when they get on the submarine that the Man in Black doesn’t get on with them.
At the Submarine the group split up as they attack the Submarine. Jack and the Man in Black stay back to cover them, which is all part of Sawyer’s plan to make sure the Man in Black doesn’t get off the Island. Sawyer leads part of the group into the Submarine. Onboard, they take the guard by surprise and get him to lead them to the captain. The other half of the group make it to the Sub with Jack and the Man in Black behind them. On the dock, the Man in Black asks Jack if he will reconsider and asks who told him he had to stay. Jack says it was John Locke, then pushes the Man in Black into the water. Suddenly the rest of the group come under fire from Widmore’s men and Kate is shot. Jack helps Sayid to get her into the submarine while Claire continues to shot back at their attackers. The Man in Black climbs back onto the dock in the chaos and starts shooting at Widmore’s men, killing most of them outright.
Inside the Sub, Jack tells Sawyer what happened above. Sawyer returns to the surface and shouts for Claire. The Man in Black realises that he is about to be tricked and runs for the Sub. Sawyer doesn’t wait for Claire, but instead closes the hatch, locking the Man in Black out. Sawyer tells Lapedes to get the Captain to dive.
On the Dock Claire is distressed that they are being left behind, but the Man in Black tells her not to worry as she really shouldn’t be on the Sub.
Onboard the Sub, Jack tries to save Kate but when he goes for his pack he finds it contains a bomb planted there by the Man in Black.
Jin calls Lapedes and tells him to get the Submarine to the surface. Jack tells Sawyer that the Man in Black wanted them to lock him out, then asks Sayid if he thinks he can disable the bomb. Sayid says he can but to do it the wires must be disconnected from the battery at exactly the same time. Sawyer steps forward to do it, but Jack stops him. He tells Sawyer that the Man in Black can’t kill them or he would have done it before now. He says that he wants them dead but can’t do it himself so he is trying to get them to kill each other. Jack tells Sawyer to trust him. Sawyer says he doesn’t and pulls the wires. The timer on the bomb stops for a moment then speeds up, racing towards zero. Sayid tells Jack that Desmond is in a well on the Island and the Man in Black wants him dead so they are going to need him. Jack asks why he is telling him this, to which Sayid replies “because it is going to be you Jack” before picking up the bomb and running with it into another part of the Sub.
The bomb goes off flooding the Sub. Sun is crushed by a unit and Jin hurries to save her. Jack gives Hurley an oxygen tank and tells him to get Kate out of the Sub. Jack then helps Jin and Sawyer free Sun. Even when they pull the unit off her she is still trapped. Sawyer is knocked unconscious and Jack has to keep him above water to prevent him from drowning. As she realises she cannot be saved, Sun tells Jin to go and leave her. Jin tells Jack to get Sawyer out while he remains behind with Sun.
As Jack leaves, Sun pleads for Jin to leave her but he refuses, telling her he loves her and will never leave her again and they drown together.
Jack arrives on the beach with Sawyer, while Hugo and Kate arrive behind them. Jack tells them that Jin and Sun didn’t make it.
On the dock, the Man in Black tells Claire that the Submarine has sunk but not all on board are dead. He picks up his pack and says he is going to finish what he started.
The final threads of Lost are now drawn so tightly that there is almost a linear story running into the final episodes of the series. There are still unanswered questions a'” mainly around what part Desmond will play, what the significance of the flash sideways are and of course what will happen to the Island in the end a'” but possibly one of the most mysterious part of the Lost mythos is who are Jacob and the Man in Black. Like Richard, the mystery is promised a solution in next week’s most anticipated episode “Across The Sea” which is a dedicated flash to show the history of the dark and light forces on the Island, and could also solve the riddle of who the Adam and Eve skeletons from the first episode are.