Monte Cook's Ptolus: City by the Spire (v. 1)

Sheva Callister is a former adventurer and treasure hunter who is supposed to be retired after the death of her partner, Parnell. But when a noble from the city of Ptolus offers her a special, mysterious reward in exchange for her retrieval of a seemingly unimportant brooch, Sheva takes the job, against her better judgment, and soon finds herself in a complex web of deception as some of the city's most infamous residents attempt to kill her and steal her hungersword.