It's 1857, and Miss Heatherton's Academy for Young Ladies is a hoarding school where girls learn to be proper young ladies. Eleven-year-old Matty, a motherless-child raised by her riverboat captain father, is fiercely independent and resists being part of the snobbish cliques her healthy, ladylike roommate Francesca belongs to. Elsa, who helps her mother in the school's kitchen and serves meals, is treated badly by the privileged students she waits on and can't fight back for fear her mother will lose her job.

When Matty learns that Elsa's secret dream is to learn to read, she convinces Francesca to ignore convention and the taunts of her friends and help make Elsa's dream come true. To do so, they must fight a battle of wits against the meanest girl in school. But Matty's bold and brilliant plan may prove who is really a proper young lady.