During one of their regular rendezvous at the Natural History Museum, the Queen and Mr Brown are transported to the strange and wonderful world of some infamous inhabitants of the London underworld - the rats! With a talking toucan and a streetwise polar bear as their guides, they are whisked through a tunnel under the Museum and launched into an extraordinary mystery tour which reveals some foul furniture, a funny smelling feast, and a spectacular rat cabaret. Beautifully illustrated and affectionately told, this is a charming tale of two best friends with a taste for adventure who love to learn about the animal kingdom.