A river of words flowed between us.
Born and raised in London, Kira and Morrow met when she spent her junior year of high school as an exchange student at the high school Morrow and James Halliday attended in Ohio. Halliday called her Leucosia.
Described as the "quintessential geek girl" obsessed with Monty Python, comic books, fantasy novels and video games, Morrow invited her to join their weekly Dungeons & Dragons gaming sessions.
In the winter of 2034, Kira was killed in a car accident on an icy mountain road just a few miles from their home.
In the movie, Kira was Karen's gamer tag which she is generally referred to as. According an obituary in Wade's Secret Hideout, Kira died in 2034 of cancer and her name at the time was Karen Underwood-Morrow.
After beating the first challenge, Parzival visits Halliday's Journals with Art3mis to view a scene on December 2, 2025, just six days before the OASIS was launched when James Halliday discusses with Ogden Morrow a date he went on with Kira. Though Kira had wanted to go dancing, Halliday took her to see a movie instead and never kissed her. Parzival reveals to Art3mis that the scene is the single mention of Kira in Halliday's Journals and he believes it to be the key to the whole challenge, seeing Kira as the mystery at the heart of Halliday's story. As Halliday loved her and it was too hard to see her or hear her name, he removed all references from Halliday's Journals and missed his chance with her. Parzival subsequently makes a bet with The Curator about Kira only appearing in that one scene and when he wins, he is given a quarter.
Art3mis then takes Parzival to The Distracted Globe, a nightclub created shortly after Halliday's date with Kira. Art3mis shares a belief that Halliday built the club to go on a dancing date with Kira, but they never had a second date and she eventually married Ogden. As a result of this and the club's anti-gravity dance floor, Art3mis believes it to be the location indicated in the clue to the second challenge. This ultimately proves to be wrong.
After nearly kissing Parzival's real-world self Wade Watts, Art3mis' real-world self Samantha Cook comes to the realization that "the leap not taken" in the clue refers to Halliday not taking the leap of kissing Kira. Through Halliday's Journals, the High Five enter a Halliday-designed remake of The Shining, the movie Halliday and Kira saw on their date. After Aech finds a picture of Halliday and Kira together in the ballroom, Art3mis realizes that Kira is the key mentioned in the clue and finds her dancing in the midst of a swarm of zombies from Mayhem Mansion in the ballroom. To win the challenge, Art3mis dances her way through the zombies to Kira and asks her if she'd like to dance. Kira states that she has waited a long time to hear that before transforming into Anorak who provides Art3mis with the Jade Key. Art3mis tells Anorak that Kira was very beautiful before traveling to the Second Gate located nearby.
After Parzival wins the Golden Egg, he is congratulated by Ogden Morrow for figuring out that Kira was the key all along. Ogden reveals himself to have been The Curator of Halliday's Journals who had lost the bet with Parzival regarding the number of times Kira appeared in the archives.
In the film, Parzival repeatedly refers to Kira as the Rosebud at the center of Halliday's story, the big mystery of it all. This is a reference to the movie Citizen Kane where the big mystery at the center of a man's life is his final word "Rosebud" which the movie centers around an attempt to figure out.