This Spells Trouble — Shelli Stevens

Arianna's a holistic witch who tries to stay out of trouble. But trouble finds her when the Hell's Ball she's attending lives up to its name. She meets a cocky vampire who's creating havoc on her hormones.  But he's also her only hope at getting through the night alive. Jake's a casino investigator, working undercover as a bartender on Halloween night. When a sexy, green-eyed witch becomes the targeted victim for a sacrifice ritual, he'll go to any lengths to save her. Especially when he realizes she may be more to him than just another casual lover.