Did you ever have an imaginary friend? A little piece of mischief only you could see? Someone that made you feel safe through new schools, new families, new homes? Sophia’s imaginary friend is called Mr. Whatsit, and he’s always there with a new joke to tell and a new game to play – that is, until the day she unimagines him. Now there’s a new imaginary friend in town – the tea-drinking, lipstick-wearing, ever-confident Margo. Can Mr. Whatsit’s childish playfulness keep him from being unimagined forever? And as Sophia’s imagination goes to war, will she manage to find peace in her new home?