The Nobles Book 4, Forgotten Realms 

Mulmaster, nicknamed the "City of Danger," is the next stop on Volothamp Geddarm's research trip for his upcoming Guide to the Monsoon, and maybe his final resting place when the bailing out of a friend from the Mulmaster prison embroils Volo in a sinister plot that threatens the tenuous political stability of all Faerûn.