That would be either "The Veiled Dragon", "Dragonwall" or "Death Of The Dragon". I think death of the dragon was part of the cormyr books, co-written by Ed Greenwood, so you can probably ignore that one and Dragonwall is part of the Empires Trilogy. I think it is "The Veiled Dragon" Try the below link
http://www.amazon.com/exec/obidos/AS...557365-7890444