After another funeral, tempers rise as the survivors’ suspicions of each other grow, and an unlikely survivor vows revenge. The events that landed Sayid on Flight 815 play out as he engages Locke in a psychological game of cat and mouse to uncover the truth about the mishap that claimed Boone’s life.
Sun allows Juliet to examine her when she learns that all of “The Others” pregnant woman died before they gave birth on the island. Meanwhile, Desmond and an unlikely nemesis collaborate to save a new island inhabitant’s life.
While trying to make contact with the outside world from a plane discovered in the jungle tree canopy, Boone Carlyle is critically injured when the plane suddenly shifts and crashes to the ground, so Jack Shephard desperately tries to save his life. The flashbacks in this episode revolve around Jack’s marriage to a former patient, Sarah.
Desmond convinces Hurley, Jin, and Charlie to follow him on a trek through the jungle after he receives a series of visions. Flashbacks reveal the time that Desmond spent with a cloister of monks. Meanwhile, a despondent Kate turns to Sawyer for companionship after seeing Jack and Juliet together.
After the missing Claire returns with no recollection of what has happened since before she boarded the doomed Oceanic flight 815, Jack and Locke formulate a plan of defense against her kidnapper, who threatens to kill off the other survivors one by one unless Claire is returned to him. Meanwhile, the disappointment Charlie feels when Claire does not remember him triggers recollections of a woman he had let down in the past.
Locke thinks he’s being sent a sign on how to get the hatch open, and he and Boone venture inland. Jack is reluctant to offer assistance when Sawyer begins to experience excruciating headaches and needs glasses.
The celebration of Jack’s return is cut short when he arrives at the beach with an Other, Juliet, whose flashbacks pick up from where they left off, showing us how she got onto the island and became an other. Meanwhile, Claire is threatened by a strange illness.
Violence ensues and a mysterious island beast makes a re-appearance when Michael and Locke clash over Walt’s upbringing. Meanwhile, Charlie is tempted to read the missing Claire’s diary, and Sayid enlists Shannon to help decipher the French woman’s map.
When Hurley becomes obsessed with the French woman and heads into the jungle to find her, Jack, Sayid and Charlie have no choice but to follow. Hurley flashes back to the hugely life-altering experience he had before boarding the plane.
Kate and Juliet are stranded in the jungle after Kate learns that there is a traitor in the survivor’s midst. Meanwhile, Sawyer’s poor attitude and selfish ways towards the beach community may earn him a vote of banishment if he doesn’t have a change of heart.
