Forsaken, The Bittersweet Vampire Chronicles, Book 4

Still convinced she’s a Fraser, Ariel slowly begins to adjust to her new life at the MacDonnel castle –and the constant presence of two overprotective warriors-- until one night when her memory comes flooding back.
Ariel's father then alarms her with the news that she has been betrothed since she was a little girl. Eventually she blows up and protests a betrothal to such a cheating swine, then stubbornly moves down to the village to stay with her adopted grandmother for a few weeks.
Rumors start spreading that her vampire warlord intends to marry soon, so Ariel returns to the Fraser’s on a mission, sees her drunken husband and comes back with more than she ever bargained for. After she returns, her emotions are a bit of a chaotic mess, and it’s in the midst of one of her volatile mood swings that she discovers a new dark ability… and picks up a chillingly predatory stalker from a fiery dimension.
Kaid quickly grows tired of Ariel living with her grandmother in the village. Wanting to hasten her return to the safety of the castle, he eventually orders Ariel's antagonistic, secret ex-boyfriend, Bran-- to be her permanent, 24-hour guard.
Meanwhile, desperate to find his missing bride, Randolph has his Fraser warriors crawling the Highlands in search of her. A cursed golden chalice is finally returned to the Frasers bearing evidence of his brides impending death which makes him even more anxious to locate her. And when he finally discovers her true identity and her whereabouts --at the hated MacDonnel stronghold-- Lord Fraser is more than eager to retrieve her…because revenge is sweet and it’s now his turn to taste it.