This is book three in the Howl's Moving Castle trilogy, but it was written quite a few years after the first two and honestly didn't need Sophie or Howl in it at all. It could easily have been written without them, with no huge loss to the storyline. This is definitely even less connected to their world than book two was!
Still, I liked this. There were lots of neat ideas in it, and the main character, Charmain Baker, was interesting to me as a bookish, stubborn girl. As the story opens, she is being sent off to keep house for her Great-Uncle William while he is away. There's nobody else to do it, so Charmain heads off to the very odd home of her great uncle, who is also known as the Royal Wizard Norland.
This house has doors that open to different places, secret passages, magical water and food and so forth, and as Charmain finds out, also an apprentice, Peter, who just shows up at the door one morning expecting the Royal Wizard.
Charmain gets involved (long story) with the King and his daughter, who are searching for something called the Elfgift, which will save their kingdom. The King is sifting through books in the royal library, and as Charmain is very good with books, she begins to assist him. These scenes in the dim, creaky library are wonderful, quiet and reeking of research. I enjoyed them!
Howl's crew gets involved when the Princess calls in Sophie, now a feared sorceress, to help them in their search. Of course, where Sophie is, Howl and Calcifer and her child are not far behind.
I liked this one, I thought the titular House was appealing, the villian (an insect like creature called the Lubbock) was suitably creepy, the plot was pretty good and Charmain was interesting. It felt a bit too farcical in some parts for me, as chaos is not my favourite plot device. But overall it was an enjoyable read. The creative set-up and the sneaky conspiracy that took a while to figure out were entertaining. I'm glad to have read all three titles in this trilogy now, although I'd probably only reread Howl's Moving Castle.