The Amazing Maurice and His Educated Rodents, Terry Pratchett
The first young adult novel in the Discworld series, THE AMAZING MAURICE AND HIS EDUCATED RODENTS is a spin on the classic Pied Piper theme with a lot of talking rats, their sidekick (also talking) cat Maurice, and a young boy called Keith. Part money making scheme, part survival strategy, as you'd expect from a Discworld novel there's entertainment to be enjoyed, and some very brilliantly constructed messages to be had along the way.
Highly recommended if you have kids, although this is number 28 in the Discworld series, it would be a pitch-perfect opening to get them hooked on the entire series.
Is Discworld ready for educated rats?
Set in the Discworld, a brand new and marvellously eccentric fantasy tale for young readers.
Maurice, an amazing cat, who has survived four years on the toughest streets in the whole of the Discworld, reckons that rats are dumb. Clever, OK, but dumb. Maurice, however, is smart -- smart enough to recognize that there’s a new kind of rat around; rats that have been eating wizards’ rubbish and can now talk. And Maurice is also smart enough to get a pretty amazing idea when he spots a kid playing the flute. Now he has his very own Pied Piper to go with his “plague of rats”. And Maurice’s money-bags are getting fuller and fuller. That is, until the group reaches the far flung village of Bad Blintz.