Kitsey is the third-youngest of the Barbour children, and she is very young when Theo comes to stay with her family. Beautiful, bubbly, and charming, she is a college student at Wellesley when Andy and Mr. Barbour die. During the weekend that they die, Kitsey was supposed to be with them, but didn’t come because she wanted to spend time with her boyfriend, Tom. Kitsey is a strong sailor, and Platt believes that if she had been there, Andy and Mr. Barbour might not have died. Following their deaths, she goes on a leave of absence from school and moves back to New York City, where she lives with a couple of roommates and works at a nonprofit arts organization. She and Theo start dating and quickly get engaged, although she keeps seeing Tom in secret. When Theo discovers this, Kitsey argues that their relationship is a way of putting on a good front and providing happiness and security to themselves and everyone around them, even if they’re not head over heels in love. However, at the end of the novel, it is implied that Kitsey and Theo never get married.