The Shield of Weeping Ghosts — James P. Davis

The past will come back to haunt them...

A group of warriors from Rashemen escorts an exiled wizard to a ruined citadel in the City of Weeping Ghosts. Once there, the wizard discovers a barbarian tribe is trying to unlock the secrets of the citadel and the weapon that destroyed it two thousand years ago.

A series that centers on the citadels - castles, keeps, fortresses, and watchtowers - of the Forgotten Realms world, each book in The Citadels series is a self-contained fantasy adventure.