Livy—short for Olivia—is the 10-year-old narrator and protagonist. She is kind and thoughtful and wants to please others. She values her parents and shares a close bond with them, evident by the anxiety Livy experiences when she is apart from them overnight. She is a recent big sister, and there are hints that her parents expect her to feel slighted by the attention that the baby receives, though this is not the case. She is intelligent and a careful thinker, using logic to uncover the mystery of who Bob is. She is cautious and apprehensive around strangers and slow to warm to them, as demonstrated by her initial interactions with Sarah. Once she is comfortable, however, Livy is friendly and fun-loving. Likewise, Livy trusts Bob and immediately seeks to make good on the promise she made to him five years prior, despite not remembering the details surrounding that initial time spent with him. That she bathes and clothes him displays a nurturing, caregiving side of Livy. At times, she is witty and teases Bob, making jokes that display her level of comfort with him. Ultimately, she is saddened when Bob is suddenly taken home by his mother.