Season 3, Episode 16:
One of Us
In flashbacks, Juliet says goodbye to Rachel as she heads off to the Island with Richard and Ethan. On the Island, Juliet works with Ethan and Goodwin, with whom she also has an affair, to fix a strange phenomenon whereby every pregnant woman on the Island dies. However, she has no success, and Ben refuses to allow her to take any women off the Island to see if that helps. She wants to go home, but Ben convinces her to stay by saying Jacob will cure Rachel's cancer if she does. Juliet confronts Ben when she discovers the tumor on his spine, accusing him of lying about the Island's ability to cure cancer, but he proves that Rachel has been cured and has given birth to a son, Julian, by showing her a video of them at the Flame.
In the present, Jack, Sayid, Juliet and Kate return to camp. Juliet is treated with hostility and suspicion by all of the other survivors. Claire suddenly collapses, coughing up blood, which Juliet claims is a reaction to drugs that she had Ethan give her to keep her alive during her pregnancy. Jack allows her to head into the jungle to find medical supplies. Although Sawyer and Sayid follow her, she convinces them to let her treat Claire, who recovers. Jack tells Juliet she is one of the survivors now.
A final flashback shows Ben and Juliet plotting for her to infiltrate the survivors as a mole. Claire's illness was the result of an implant placed in her by the Others, used to create a crisis for Juliet to win the survivors' trust.
Tropes in this episode include:
- All According to Plan: As Juliet is setting up her tent, there's a flashback to her talking with Ben, revealing that everything from being tied up with Kate to Claire's illness was part of a plan. Ben then gives her a gas mask and says "See you in a week."
- Arc Number: According to Mikhail, there were 324 passengers and crew aboard Flight 815. 324 is three times 108, the sum of the numbers.
- Call-Forward: When Juliet visits Ben to tell him about his tumor a few days before the plane crash, he tells her that he's just started reading Carrie, the book that Juliet chose for the book club meeting the day of the crash in "A Tale of Two Cities".
- Cross-Referenced Titles: With Season 2's "One of Them". Both episodes revolve around whether or not a new arrival to the survivors' camp is one of the Others.
- Even the Loving Hero Has Hated Ones: Even Hurley, the show's ultimate Nice Guy, treats Juliet with suspicion due to the Others' past crimes against the survivors.
- Instant Sedation: In the flashbacks Juliet chugs the glass of juice containing the sedatives for the submarine trip and immediately passes out. After she finishes the drink Ethan tells her that she shouldn't have done it, indicating that they actually didn't want her to be knocked out so fast.
- "The Reason You Suck" Speech: Juliet gives one to Sawyer and Sayid when they try to stop her getting the medicine for Claire, pointing out that they are the last people who should be casting aspersions about her trustworthiness."You know it's interesting... that you two are now the camp's moral police. I'm curious, Sayid, how long was it before you told everyone on that beach exactly how many people you've tortured in your life. Do they know about Basra? And I'm sure the first thing you did when you got here, James, was to gather everyone in a circle, and tell them about the man you shot in cold blood the night before you got on the plane. So why don't we just skip the part where you two pretend to be righteous. I'm taking that medication back to Claire. And you're gonna let me. Because if she doesn't get it, she's gonna die. And the last thing, that either of you need right now, is more blood on your hands."
- Series Continuity Error: Juliet mentions Sawyer's murder of Frank Duckett in Australia. However, she says it happened the night before the flight. It was actually about a week beforehand, as Sawyer was in the police station three nights before the flight for headbutting an Australian government minister.
- Toplessness from the Back: Juliet is seen this way while sitting in bed with Goodwin.
- You Are Fat: Sawyer refers to Charlie, Hurley and Aaron as "Three Men and a Baby", saying that he counted Hurley twice.
