A cat, two guinea pigs, and a colony of brave sewer rats band together in order to save Freddy, a golden hamster, from an evil scientist who's discovered that Freddy can read and write, and plans to hamster-nap him in order to dissect his brain.

The characters in Freddy's latest novel, an evil fifteenth-century poacher and his ferrets, mysteriously come to life, endangering Freddy and his friends and drawing them to an English castle near where the poacher once lived.