It was fine; kind of a middling entry in the series. Very short, as Twistaplots tend to be, which hampers the story, but the narrative still manages to be somewhat varied. There's an interesting bit with a secret wizard's code, but it isn't used for a puzzle or anything; if you look at it, your character just instantly memorizes it. Bit of a wasted opportunity that knocks three pages off an already short book.
You find a book, you cast some spells, you make a few choices. Good enough.