Kaitlin Greenbriar

Kaitlin "Katie" Greenbriar (born December 12, 1973) is the eldest child of Janice and Terrence Greenbriar, and elder sister of Sam. She is a twenty-one-year-old woman who, after having spent her sophomore year of college abroad, returns home late one night in June to find her family gone with few clues as to where they have gone. She explores the new house they had moved into during her absence in an effort to uncover where her family is.

Early life
Katie is the eldest daughter in the Greenbriar family, having been born to Janice and Terrence Greenbriar in 1973, three years after her parent's marriage. A studious student, she left for a trip abroad in Europe a few months prior to her 21st birthday. She would spend an entire year overseas.

Europe trip
Katie organised her passport several months before leaving for her European trip. On June 7, 1994, she flew to Amsterdam on flight 881 from New York (after a connecting flight from Portland to Cincinnati).

The earliest postcard sent to her family was from Paris on August 2, 1994.

Returning home
Upon her return home at 1:15 A.M. on June 7, 1995, she finds her family's new house, willed to them by their father's late uncle, to be completely empty. Her sister Sam had left her a note on the front door for Katie to find. In it, Sam apologizes for not being home to greet her elder sister, and urges Katie not to look for her; Katie ignores the request and begins searching the house, coming across letters and journal entries that Sam has written for her.

Upon unlocking the attic, a room which appears to be used predominantly by Sam as a darkroom, Katie locates one last letter written to her. In it, Sam tells her that she was so sorry that she was not be able to tell Katie all of her experiences in person, and hopes that her sister will not be sad or mad, and that she would understand. She concludes the letter telling Katie how much she loves her and promising her that they would see each other again someday.

Sam
It is clear from the way Sam addresses Katie in her journal entries that the sisters are very close. As is evident in Sam's first entry, Katie is the only person to whom Sam is comfortable speaking her mind. She likely did so for much of her childhood as she had few female friends, to the extent that Sam believes Katie to already be aware of her sexuality. In her first year at the new house, Sam continues to talk to her sister indirectly through her journal, which is a significant source of comfort for her.

Sam tells Katie everything about her relationship with Lonnie, sparing only the most intimate details – which Katie has no interest in knowing anyway. She also entails her struggles in coming out to their parents and Lonnie's eventual departure. When Lonnie asks Sam to come find her and begin a new life together, Sam regrets that she was unable to see Katie's return, but leaves one final journal entry telling her how much she loves Katie and promises that they'll see each other again.

Terrence and Janice
Katie loves her entire family and regularly sent them postcards throughout her year abroad. There are indications of the more personal nature of her relationship with her parents through Sam's journals and other notes around the house. Terrence would often joke about sending Katie to "the Nunnery" whenever she brought boys over to their house. At least one of her parents would also complain about how Katie left lights on around the house, a habit that Sam shared.