This is a fantastic book! I read it in less than twelve hours, and that's with working and eating in the middle of that!
Where to begin? The characters are wonderful. Sham is a complex character, with a painful past but the strong will to survive it and move on. She is wily enough to survive life in Purgatory, the Southwoods slum, yet tender-hearted enough to learn to care for people she was used to hating. Kerim is humorous, regal, dangerous, and intelligent--all the things we want from a hero! The supporting characters are wonderful; Dickon, Elris, Talbot, Lady Sky all make the story better with their special personalities.
The writing is great. The dialogue is excellent, with witty repartee between the characters that is absolutely believable and absolutely hysterical. The description of surroundings and clothes are wonderfully detailed. I could see the action in my mind as I read. My one complaint about the writing would be the infrequent shifts in the third-person point-of-view; usually the POV character was Sham, but very occasionally is changed to Kerim, the demon, and a couple others.
The plot is intriguing...a demon stalking the halls of the Castle, with a thief/magician hired to pose as the Reeve's Mistress in order to solve the mystery. And though you may have suspicions about the demon's identity, your first two guesses will be wrong!
I highly recommend this book, and I am actively seeking out others by this author!