Feast of Fools by Rachel Caine

In the town of Morganville, vampires and humans live in relative peace. Claire Danvers has never been convinced, though-especially with the arrival of Mr. Bishop, an ancient, old-school vampire who cares nothing about harmony. What he wants from the town’s living and its dead is unthinkably sinister. It’s only at a formal ball, attended by vampires and their human dates, that Claire realizes the elaborately evil trap he’s set for Morganville.