Enchanted Glass

A novel by British author Diana Wynne Jones. Professor Andrew Hope has inherited his grandfather's estate, along with his field-of-care. Thing is, he can't seem to remember all the advice his grandfather used to give him about how he was supposed to do that. Not only that, but he has to put up with Mrs. Stock, the housekeeper, who cooks hardly delightful dinners every time he does anything in the house such as arranging furniture. To make things even more complicated, 12 year old orphan Aidan Cain shows up on his doorstep, and he's being hunted.

The novel was published in April 2010 and it was intended for an audience of 9-12 years of age.

Tropes used in Enchanted Glass include:

Absent-Minded Professor: Well, some see Andrew as this, since he spends most of his time staring at a computer.
A Storm Is Coming
At the Opera Tonight: At the local festival, rather.
Barrier Maiden: Andrew is a rare Spear Counterpart
Evil Counterpart: Nearly everyone has a fairy counterpart, though not all of them are evil. Tarquin and Puck, and Stashe and Titania are examples of good/evil counterparts; good/good examples are Shaun and Groil, and Andrew and Aidan.
The Fair Folk
Foreshadowing: The names of the horses that rank in the daily races are Stashe's way of telling foreshadowing. Andrew thinks it works after meeting Rolf and WPC 92, since the horses that ranked on that day were "Dogdays" and "Heavy Queen."
Laser-Guided Amnesia: Andrew accidentally did it to himself; a combination of his mother telling him not to listen to his grandfather and his own scholarly pursuits led to him blocking out everything he learned about magic until something actively reminds him again. Also what happens to the rest of the townsfolk after the storm passes.
Lethal Chef: Mrs. Stock usually cooks cauliflower cheese every time she is disgusted with Andrew. Though, Aidan does not seem to mind eating this.
Let's Get Dangerous: Andrew is generally mild-mannered unless you push him too far. Or threaten his field-of-care. In which case him may literally blow you off his land.
Not Using the Z Word: The Fair Folk are only referred to as "those who don't use iron."
Offing the Offspring: What Oberon is trying to do to Aidan.
Our Werewolves Are Different: They can change at any time.
This Means War: Andrew is really protective of his field-of-care.
Your Mind Makes It Real: Tarquin's replacement leg