Lizzie, Ella, and Betsey Best grew up believing they were identical triplets. Then they learned the truth... and no one else can know. Now, to the outside world, the Best family appears to consist of a single mother with one seventeen-year-old daughter named Elizabeth. Lizzie, Ella, and Betsey take turns going to school, pursuing extracurriculars, and even dating. Then Lizzie meets Sean Kelly, the one person who can help her realize she's not a carbon copy of the others - she's an individual with unique dreams and desires. Digging deeper into her background and her mother's role in her life, Lizzie begins to dismantle the delicate balance of an unusual family that only science could have created.