Katie is the 12-year-old protagonist of the story. She lives in New York City with her mom. At the beginning of the novel, she is best friends with Bethany, and spends most of the narrative trying to save enough money to attend one week of summer camp. As the novel progresses, Katie proves herself to be resourceful. Her first attempts to earn money are fruitless, but she shows great perseverance and is eventually rewarded when Ms. Lang hires her to cat sit. Through this experience and her new relationship with Ms. Lang, Katie’s interests begin to shift. Learning how to best care for (and control) the mischievous cats teaches her the joys and rewards of responsibility.

While Katie is already a kind, considerate, thoughtful person—evident in her vegetarianism and the way she cares for the cats—Ms. Lang introduces her to the idea of animal rights and makes her more socially aware, which profoundly deepens Katie’s understanding of right and wrong. As Katie grapples with these new ideas and problems, she grows apart from Bethany, who is undergoing her own changes at camp. While this initially upsets and frustrates Katie, the novel uses their relationship to demonstrate that it is natural for relationships to change over time, especially when, like Katie and Bethany, one is figuring out who one is and the type of person one wants to be in the world.