It's the first book in the series. It was released in 2007

Emmy starts to relize that no one is talking to her. She finds out that he nanny, Mrs. Barmy, is using a device so the kids don't notice her.

Her class pet, the rat, starts to talk to her.

He can make people talk to rodents, and shrink.

At the end the solve the Mrs. Barmy maham and turn her into a rat.