Deus Ex Machina (''Lost'')

Flashbacks

In flashbacks, a younger Locke meets a mysterious woman (Swoosie Kurtz) in the discount superstore in which he works. After an initial meeting, Locke later notices the same woman watching him in the store's parking lot. He chases after her to confront her and she explains that she is his birth mother, Emily Locke. Locke asks about his father and Emily claims that Locke doesn't have a father because he was immaculately conceived. Undeterred, Locke hires a private investigator who finds Locke's father, Anthony Cooper (Kevin Tighe). When Locke visits his father's affluent home he is welcomed with open arms. Locke forms a strong relationship with his father, who now frequently takes him hunting. One day Locke arrives at the home early and discovers his father receiving dialysis treatment. Eventually Locke offers one of his kidneys to save his father. After the surgery, Locke wakes up in the hospital to find that his father has discharged himself home for private care and abandoned him. Emily arrives to explain that when Anthony realized he needed a kidney, he tracked down their son and paid her to make contact with him, presumably for the sole purpose of getting the transplant. Devastated, Locke pulls himself out of the hospital bed and drives to his father's home, but is regretfully turned away by the gate guard, with whom he has become friendly. As he drives away, Locke breaks down over the betrayal.

On the Island

It is Day 39, October 30, 2004, on the island, Locke and Boone Carlyle (Ian Somerhalder) build a trebuchet in an effort to break open the hatch window. When this fails, an exasperated Locke pounds the hatch. Boone notices a shard in Locke's leg but Locke says he feels no pain and that night he discovers he's losing the feeling in his legs.

Meanwhile, Sawyer is suffering from headaches and a sensitivity – Jack diagnoses this as farsightedness caused by the strain placed on Sawyer's eyes due to his large amount of reading since arriving on the island. Using spare glasses found from the wreckage and Sayid's engineering skills, Jack offers Sawyer a new pair of glasses to read with.

Locke and Boone are at the hatch again, and while Locke is undeterred Boone is becoming hopeless and views their continued efforts to open it a waste of time. Locke asserts that the island will send them a sign about the hatch, at which point he notices a Beechcraft 18 crash in the jungle, and observes Boone uttering the phrase "Theresa falls up the stairs, Theresa falls down the stairs". Locke awakens revealing this scene to be a dream; he wakes up Boone to head out in search of the aircraft, but Locke has suddenly found himself losing the use of his legs as he can no longer stably walk. During the walk, they discover a decayed body in a Catholic priest's clothing, carrying Nigerian currency and an unloaded handgun. When Locke falls, Boone tries to convince him to return to camp, but Locke convinces him to continue by mentioning the phrase he heard Boone say in his dream. Boone reveals that Theresa was his nanny when he was a child who broke her neck on the stairs one day; at this point, the two spot the plane in a tree.

As Locke is unable to walk, Boone must ascend the tree to search the plane alone. He discovers a trove of statues of the Virgin Mary filled with heroin, the decayed body of another "priest", and a working radio. Boone sends out a distress call on the radio and a male voice answers, "Is someone out there?" to which Boone responds, "We are the survivors of the crash of Oceanic Flight 8-1-5." The voice answers "There were no survivors of the Oceanic Flight 8-1-5!" (In future episodes, this was changed to, "No, we're the survivors of the Oceanic Flight 8-1-5!") At this point the teetering plane shifts from Boone's movements and suddenly falls to the ground, crashing nose first. Frantically, Locke struggles to his feet, hoists a critically injured Boone on his shoulders, and returns to the camp.

Locke carries Boone to the cave and lies to Jack Shephard (Matthew Fox), telling him that Boone fell from a cliff while they were hunting. Jack begins treating Boone, and Locke disappears into the jungle to return to the hatch. Locke pounds on the door and screams in anguish at how he has done everything the island has asked him to do, and how he is both losing his ability to walk and unable to open the door. Suddenly the hatch window is illuminated.