I was one of the playtesters for this adventure and it is pretty cool. It features nightmare-magic which screwed us over royally, but once we got a nightmare-magician of our own it was a LOT easier!
The rules for magical stones are also most excellent.
Well written material. It says you need the Lost Roads of Lociam core rules to play it, and that is true, but download it just for the inspiration. You can't beat free.