Lord of the Vampires (Harlequin Nocturne)

"Once upon a time...the Blood Sorcerer vanquished the kingdom of Elden.
To save their children, the queen scattered them to safety and the king filled them with vengeance.
Only a magical timepiece connects the four royal heirs...and time is running out...."
Nicolai the Vampire was renowned for his virility, but in a twist of fate "The Dark Seducer" had become a sex slave in the kingdom of Delfina--stripped of his precious timepiece and his memory. All that remained was a primal need for freedom, revenge--and the only woman who could help him.
In her dreams, a wanton vampire called to Jane Parker, drawing her to his dark sexuality and his magical realm.
But for a human, all was not a fairy tale in Delfina. Jane was the key to Nicolai's memory...but exploiting her meant dooming the only mortal he craved.