Bad Blood : Bad Witch, #5

Robyn Bachar's Bad Witch series blends romance and urban fantasy in a setting filled with magic, vampires and meddling faeries.
How do you convince a skeptic to reverse your curse?
Natividad Houlihan travels the world searching for stunning historical sites with juicy secrets...and ghosts. Nati doesn't believe in the supernatural, but as a location scout for the Spirit Seekers paranormal investigation show she works for true believers. The team is thrilled at the opportunity to investigate an infamous Spanish haunted mansion--but the price of admission requires Nati to spend two weeks stumbling around in the dark searching for EVPs and light anomalies. Nati's only company is Cris, the estate's surly, sexy caretaker, who intrigues her during the day and stars in her vivid erotic fantasies at night.
Don Cristobal Mendoza loved unwisely and paid the price for his indiscretion, suffering a vicious curse that trapped him within the bounds of his ancestral estate. By day he is the manor's mysterious caretaker, and by night he is the shadow demon who stalks its halls. For centuries he has hidden his condition from the world as he despaired of ever being freed from his curse.
Nati is determined to unearth the secrets Cris has kept for centuries and bring his past to light, but Cris can't resist the chance to indulge his dark desires with a bold, beautiful American skeptic. As the balance of magical power shifts, they must work together to break the curse before Cris's time runs out.