Betrayed (2007)

Zoey, High Priestess in training, has managed to settle in at the House of Night and come to terms with the vast powers the Vampyre Goddess Nyx has given her. Just as she finally feels she belongs, the unthinkable happens: human teenagers are being killed, and all evidence points to the House of Night. While danger stalks the humans from Zoey’s old life, she begins to realize that the very powers that make her so unique might also threaten those she loves.