Waking for Winter. Philadelphia Coven Chronicles, #4

The Philadelphia Coven has thwarted the Order of the Serpent's every attempt to destroy their city only to draw out the scariest nightmare from the Otherworld, the Caoranach. One of the Coven's own, Cami Akiyama, has already met this creature-the very monster who tortured her, branding her with a mark. Given Cami's history with the big bad, the Coven leader assigns her a bodyguard, none other than the gorgeous and lethal necromancer, Dante Martinez, the ex-boyfriend she disappeared on years ago.
One conversation confirms the spark between them never died, and based on the way Dante flirts, he won't allow that flame to extinguish out without a fight. No one has ever compared to Dante and the incendiary passion he inspired in her, but the Caoranach broke her-Cami's too damaged for any sort of relationship. Not like that stops him. If anything, he fights harder for the memories of a love that kept her sane on the bleakest nights.
And despite every effort to distance, she finds herself falling for him all over again. Except the Caoranach isn't finished with her-the branded mark holds the secret to the city's destruction or salvation, and Cami stands in the center of the storm.