Mister Monday, by Garth Nix

Arthur Penhaligon is the asthmatic new kid at school. He didn't know about the Monday run and doesn't have a doctor's note explaining how very bad his asthma is - so the teacher makes him run. When he's lying in in a field, collapsed and barely breathing, something strange happens that might be a hallucination, but isn't. A fragment of the Will left by the Architect has escaped the dead sun where it has been imprisoned for millennia, and manages to trick Mister Monday into giving the lesser key to Arthur, fulfilling the bare letter of the law of the Will (since Arthur is an heir and very near death).

This sets into motion a chain of events. Dog-faced men and some of Monday's minions including Monday's Noon, come after the key. Soon, there is some kind of plague and the town is under quarantine - which Arthur is particularly sensitive to because his birth parents were killed in a flu epidemic when he was little, and his adoptive mother is an epidemiologist. Arthur knows the sleeping plague is connected to the creatures coming after him, so he enters the odd, large, convoluted house that has shown up in his neighborhood (which his parents can't see). This is the Architect's house, built on Nothing, which borders on the secondary realms such as our world.

Arthur has a series of adventures and mishaps as he travels through the House and meeting an odd cast of characters, including: Suzy Turquoise Blue, an ink-filler who followed the piper into the House from a different century; the Old One in the coal cellar (a sort of Prometheus); Monday's Dusk; and even snakes that viciously attack any words ow writing. As the Will, in the form of a jade frog, works to help him claim the rest of his inheritance - the greater key - all Arthur really wants is to go back home and find a way to stop the plague and save his family.

Title:	Mister Monday
Author:	Garth Nix
Date published:	2003
Genre:	Children's Fantasy
Series:	Keys to the Kingdom
Number of pages:	384
Notes:	loan/gift from Catey