Dead Travel Fast by Deanna Raybourn

With a modest inheritance and the three gowns that comprise her entire wardrobe, Theodora leaves Edinburgh and a disappointed suitor far behind. She is bound for Rumania, where tales of vampires are still whispered, to visit an old friend and write the book that will bring her true independence.

She arrives at a magnificent, decaying castle in the Carpathians, replete with eccentric inhabitants: the ailing dowager; the troubled steward; her own fearful friend, Cosmina. But all are outstripped in dark glamour by the castle's master, Count Andrei Dragulescu.

Bewildering and bewitching in equal measure, the brooding nobleman ignites Theodora's imagination and awakens passions in her that she can neither deny nor conceal. His allure is superlative, his dominion over the superstitious town, absolute Theodora may simply be one more person under his sway.

Before her sojourn is ended or her novel completed Theodora will have encountered things as strange and terrible as they are seductive. For obsession can prove fatal... and she is in danger of falling prey to more than desire.