Gill is running from something, and has wound up in a small cottage on the Cairndonan estate of Dame Juliana Flagg, desperate for solitude. But it is clear from the very beginning that being left alone is not going to solve her problems. The entry of several rather nosy people, while quite upsetting to Gill, is not nearly as upsetting to the reader. Gill is not Aetherial, yet she finds herself in the Spiral one day with some fascinating consequences. Gradually the mystery of what is really happening at Cairndonan, and why Dame J hasn't sold a piece of artwork in 15 years is revealed. Naturally the revelation involves some adventures in the Spiral and a lot more insight into the workings of the Aetherial community.
It could have easily been a black and white story of good vs evil. One of the characters, Rufus, is very definitely evil, quite possibly the devil, and yet the "good guys" weren't nearly as good as they seemed. There was also the interesting question of how important it is to punish someone for a crime committed over a thousand years ago. This was a fun book to read, hard to put down, easy to get lost in, with a totally satisfying ending - you can see how the characters are now free to get on with their lives, they have lots of different options open to them which are all going to be far more interesting to the characters themselves than to the reader, and so you are happy to let them get on with their lives while still longing for a sequel because it is the setting itself which is so fascinating. Our own familiar world, interleaved with that of the Spiral where the Aetherials can take on their alternate forms, often more animal than human, with their very different life-spans. I'm looking forward to the next one!