Maurice is the Station Mouse, and so he must follow The Station Mouse
Handbook: Rule 1: A Station Mouse must remain unseen. Rule 2: A Station
Mouse must never go out in the daytime. Rule 3: A Station Mouse must
never approach the passengers. Now, there's a reason why these rules
exist: people do not like mice. And if Maurice breaks the rules, even to
help a little boy who has lost something very important, there's going
to be a price to pay. There are funny details to spot on every page,
including his tiny spider side-kick. Each endpaper is a map of the train
station, showing where the Station Mouse goes, and where is dangerous!