Harry "Dit" Sims and Emma Walker are the unlikeliest of friends. Emma, the educated twelve-year-old daughter of Moundville's new postmaster, is all wrong as far as Dit's concerned. Dit was told the new postmaster would have a boy his same age, not a girl. But the rest of the town is more surprised by the Walker family's color than whether Emma's a boy or a girl. But that makes no difference to Dit's mother. Her rule is to be nice to everyone, and before long, Dit's glad about Mama's rule. Emma's not like anyone he's ever known. Emma is the first person to ever listen to Dit. Emma also makes Dit think, and about things he's never given much thought to before, like why the colored kids and the white kids can't go to school together. Soon Dit's thinking about a lot more when Doc, who is black and the town barber, is accused of a terrible crime. Dit and Emma know he doesn't deserve to be punished, and together they come up with a daring plan to save Doc from the unthinkable.