Claire Littleton (Emilie de Ravin) is a pregnant survivor of the crash of Oceanic Flight 815 on "Lost." Before the crash, she had been a tattoo artist and accidentally became pregnant. Deserted by her artist boyfriend, Claire was on the flight to Los Angeles to meet prospective adoptive parents for her unborn baby. She was cajoled into taking the doomed flight by a psychic friend who had seen her baby's future, and knew that she needed to be a parent to the child.
On the island, Claire is a loner and ignored by everyone except for Charlie Pace (Dominic Monaghan), a washed up rocker, and Jack Shephard (Matthew Fox), a surgeon who looks after Claire's pregnancy. Claire is kidnapped and taken to the DHARMA hospital, where she is drugged. While there she has moments of clarity where she hears people talking about keeping her baby and sending her back to the survivors. One night a young girl wakes her and tells her that these people intend to cut her baby out of her and kill her, and that she has to escape and go back to the survivors.
Claire later wakes in the woods and makes her way back to the camp but she cannot remember anything about where she has been or what happened there. She eventually gives birth to a baby boy with the help of Kate Austen (Evangeline Lilly) and names him Aaron (William Blanchette). Claire doesn't trust the other survivors with the baby and becomes apprehensive. Charlie helps Claire with the baby until Mr. Eko (Adewale Akinnuoye-Agbaje) tells Claire that he is using heroine that he has stashed away. Claire confronts Charlie and tells him to stay away from her and the baby. Charlie can't stay away however, and steals little Aaron believing he should be baptized. Claire is furious about this but asks Mr. Eko to baptize her and the baby.
Aaron starts to get sick, and Charlie gives a case of vaccines and a pneumatic injector to Claire for her and the baby. Claire asks the psychologist Libby Smith (Cynthia Watros) to help her remember what happened when she was kidnapped. Libby agrees and Claire starts to have memory flashes. Frightened by her memories, she and Kate go off to find the medical facility she had been kept in. After Libby dies, Charlie and Claire are reconciled.
A lightning storm threatens their lives but Claire won't leave her home. She, Charlie and Aaron survive because the lightning strikes a lightning rod put up by Desmond Hume (Henry Ian Cusick) instead of their shelter. On another day, while Claire is swimming, she is pulled under by the ocean current, knocked unconscious and floats out to sea. Desmond saves her and revives her. She doesn't know that Desmond is psychic, and thanks him for saving her.
Claire wants to use the seagulls that have tracking bracelets to carry a note about flight 815, to the scientist that tracks them. Charlie wants no part of the plan and Desmond seems bent on stopping her. Desmond catches the seagull and explains to Claire that he is clairvoyant, and that Charlie is going to die. Claire promises Charlie he won't die, she ties the note to the bird and releases it. Later, Claire is under some sort of spell and leaves her baby at the foot of a tree before wandering off, only to be seen on and off the island later on.
"They stuck me with needles, they branded me."
"They tried to kill my baby."