The characters on LOST have many secrets they keep from each other. This page serves to keep track of as many secrets as possible, including who knows what.
Kate
- Kate killed whom she thought was her step father when she found out that he was really her biological father, thus starting her life on the run.
- She was finally captured by a U.S. Marshal, Edward Mars, in Australia, and was being escorted back to the U.S. on Flight 815.
- Mars is hit by falling luggage and goes unconscious during the plane crash, allowing Kate to unhandcuff herself.
- After the crash, Mars is so severely injured that he barely manages to tell Jack of Kate's fugitive status.
- Hurley, Sawyer and Sun also find out early on.
- Sawyer exposes Kate's secret to everyone in Born to Run in an attempt to remove the suspicion that he poisoned Michael.
Secret's status: Known by all
- Kate was the one who urged Sun to poison Jin.
Secret's status: Known only by Sun.
Sun
- Sun learns English, from Jae Lee, prior to boarding Flight 815 as part of her plan to leave Jin.
- When the plane crashes, no one knows (not even Jin) that Sun can speak English. Because of the language barrier, the Korean couple is kept out of the loop.
- Sun reveals her secret first to Michael, to explain that Jin assaulted him for stealing Jin's watch.
- Kate discovers Sun's secret based on her reactions to Kate's words while they are gardening.
- Everyone finally learns about her ability to speak english when she defends Jin against accusations that he burned the first raft.
Secret's status: Known by all
- In Born to Run, Michael gets sick and Jack determines that someone poisoned his water bottle.
- Kate and Sawyer are early suspects.
- Jack confronts Sun, who confesses she didn't want Jin to leave, and "only used enough to make him [sick]." Michael inadvertantly drank from Jin's water.
- Jack tells Sun that he won't tell anyone.
- Later in the episode we find out that Kate suggested the poisoning; only Sun knows this fact.
Secret's status: Known by Jack and Kate. Kate's involvement known only by Sun
- Sun and Jin cannot have children.
- Jin thinks this is because of a problem with Sun's reproductive system. But we find out that it is due to a problem with Jin.
- Sun keeps this secret until she finds out she is pregnant.
Secret's status: Pregnancy known by all, Jin's sterility only by Sun, Jin and their doctor.
Locke
- Locke was in a wheelchair for four years before the crash, but since he was pre-boarded prior to anyone else getting on the plane, no one knew of his disability.
- After the crash, Locke found himself able to walk.
- Walt says to Michael "Mr. Locke said a miracle happened to him." How much Locke elaborated on this fact to Walt is unknown.
- Upon approaching the drug smugglers plane for the first time, Locke's legs start to revert to their paralyzed state.
- Locke reveals his secret to Boone just before he is injured exploring the drug smugglers plane.Boone dies before telling anyone Locke was paralyzed.
- Locke wheeled up to Rose in the airport to pick up the medication she had dropped. Later when he tells her that it's going to take four weeks to recover from the blast door crushing his legs, she replies "You and I both know it's not going take that long."
Secret's status: Known only by Rose
- Only Locke has seen the Hieroglyphics on the Countdown Timer and chose not to reveal to anyone what he had seen.
- The false Henry Gale claims he saw the hieroglyphs when the numbers flipped back
Secret's status: Known only by the false Henry Gale.
- Only Locke has seen the map illuminated by the blacklight on the blast door of the Hatch.
Secret's status: Known only by Locke.
Hugo "Hurley" Reyes
- Hurley is a multi-millionare
- Wins the Mega Lotto Jackpot by playing the Numbers he got from Leonard.
- Owes Walt $83 000 he bet playing Backgammon. He assures Walt, "you'll get it."
- Tells Charlie his net worth, but Charlie doesn't believe him.
- Tells his story on separate occasions to Rousseau and Jack.
- On the raft, Sawyer reads the message Hurley wrote for the Bottle, but doesn't recognize Hurley's real name. (He says, "Who the hell is Hugo and how's he got a 160 million dollars to leave to his mom?")
- After winning the lotto, Hurley appeared on a Korean TV station, seen during the episode ...In Translation.
Secret's status: His multimillionaire status is known by Jack and by Charlie but Charlie doesn't believe it.
- Hurley tells Jack that Hurley isn't his real name, but won't tell Jack why he's called Hurley.
Secret's status: Known only by Hurley
- Hurley feels responsible for the death of two people that resulted from an accident where a balcony collapsed. After the accident, he was admitted to the Santa Rosa Mental Institute.
- At the hospital, he had delusional imaginary friend named Dave, where he heard the Numbers from a fellow patient named Leonard.
- Libby was also in the psych ward, but as of yet we don't know if they met.
- Tells Jack of his psych ward stay in Man of Science, Man of Faith
Secret's status: Dr. Brooks knows of his stay and about Dave. Libby knows he was in Santa Rosa and may or may not know about Dave. Jack knows about his stay but not about Dave.
Charlie
- As part of Sawyer's plan in The Long Con, Charlie attacks Sun, making it look like the Others are becoming more aggressive.
- It could also have something to do with Charlie getting back at Locke for humiliating him in front of every one in Fire + Water.
- Charlie is a recovering heroin addict
- Now known by at least Jack, Locke, Hurley, Claire, Sawyer, and Mr. Eko. It's not clear if his addiction is generally known.
Walt
- Burned Michael's first raft.
- Locke figured out Walt's actions and confronted him. Walt would go on to confess to Michael.
- Supposedly caused a bird to be killed by smashing to a door. His stepfather told Michael about this as to imply Walt was a "different" person.
Libby
- Was in Santa Rosa Mental Institute
Rose
- Has a terminal illness, which she believes to be cured because of (and while she remains on) the island.
- Knows Locke should be in a wheelchair