Super-Saver Mouse — Sandi Toksvig

An unusual adventure story, ideal for beginner readers.
     
Boris is a 'tube' mouse -- he lives in the underground railway in London. His best friends are his cousin, Kicker, and Heavy Duty, the station cleaner. One day, Boris discovers an accident and has to devise a brave and clever plan to save the day.

Illustrated throughout by whacky cartoon pictures, this is an ideal story for children who have just learned to read.