Simon is both the author and protagonist of this book. She is Beth’s older sister and a published writer. She lives a solitary, lonely life. She often works 16 hours a day between writing, teaching, and running events at a bookstore. She carries enormous guilt about being a bad sister to Beth and for not marrying her ex-boyfriend, Sam. At the start of the book, she is hoping to get to know Beth a little better and hoping she’ll be able to stand her company for more than a few hours. By the end of her story, Rachel has healed her self-proclaimed icy heart, married Sam, and become an advocate for people with intellectual disabilities. She and Beth maintain a loving and close relationship. 

Beth is Rachel’s younger sister, a woman diagnosed with an intellectual disability and living on her own. Beth chooses not to work and instead spends her days riding the city buses. She makes deep connections with her favorite drivers and some friendships with passengers. She is in love with her boyfriend, Jesse, and they have been together for 10 years. Beth is a vibrant, fun woman who loves to laugh and listen to music.