Masque (The Two Monarchies Sequence). Two Monarchies Sequence, #5

Old maids! Murder! Masked Beast Lords!Lady Isabella Farrah didn't expect a proposal from a masked man at the Annual Ambassadorial Ball-nor did she expect a murder. She got both. Happily for society at large, Isabella is of the opinion that noses were made for sticking into other peoples' business, and she is delighted to do just that in the service of the murdered man-and perhaps in service of a certain Beast Lord, who is not as grateful as Isabella thinks he ought to be.
Now it's just a matter of finding a murderer in a society of malcontents, traitors, and bad dancers. It's a game of masks, and the Beast Lord isn't the only person hiding behind one.