Lynne Jonell

Ten-year-old Emmy wants to be an ordinary girl, but the evil nanny Miss Barmy, now a rat, has trapped five of her former charges and when she uses them to steal jewels belonging to Emmy's parents, it is up to Emmy, Joe, and their rodent friends to stop her.

Duncan, eleven, is very smart with the rare ability to speak Cat, but his mother has always insisted he appear only average, and when a perfect test score draws attention to him, he not only discovers the wisdom of his mother's rules, he finds himself crossing the seas on a quest for his true identity.