Did you know that the Rat and Mouse Club of America also hosts fiction? They have a mini novel called "Mouse Knight" by Cutter Hays as well as a sequel and spin-off. Although I was a little offended by the cover picture showing a mouse using a rat as a steed, but it turns out that this was a voluntary arrangement in a time of crisis and Mike (as the rat is called) is a true and loyal friend. In fact, all the rats were pretty good sorts (once you got past the mouse-eating thing). I'm always pleased to see positive role models for rats, so I thought I should give a nod in their direction.
The story itself is well written, the best thing I've read online in a long time. It initially had echoes of The Tale of Despereaux ("Mouse Knight" was written before this novel), with a mouse starting in poor circumstances reading stories about knights and chivalry and aspiring to become a knight, but it soon branches off in another direction.