Shadow of the Moon (Dark Moon, 4) by Marie Medina
Rebecca and Chris should have been planning their wedding, but with Gerard gone and the other vampire leaders forcing Rebecca to take her place as a clan leader, they had little time for such happy thoughts. Their troubles worsen when Blake, a powerful vampire who had stayed silent at first, comes forward to threaten Rebecca and those she protects. If she marries Chris, a former vampire hunter, Blake will declare war on her and anyone who supports her. The werewolves who protected her and Gerard when they needed friends the most will suffer if she loses her power and authority, so she cannot step down but refuses to give in.
When Chris disappears, she tries to find Gerard. Did Chris leave to protect her? Or had something worse happened? Would she find Gerard? And even if she did, would he be able to help her?