Though 13-year-old Mary is happy to keep quiet about the secret instruction she receives at Miss Prudence Crandall's private school for the daughters of the richest families in New England, Mary's sister Sarah glories in the fuss she creates when she is openly admitted. When Miss Prudence replaces the school's white students with little misses of color, all sides of the anti-slavery movement want to use the school to further their own agendas-with Mary and Sarah caught in the middle!