The Mayfair Moon - The Darkmoon Saga, #1

After a nightmarish encounter with a werewolf in the Georgia woods, seventeen-year-old Adria Dawson loses her sister but gains the attention of a mysterious young man and his legendary family. Soon after the tragic event, she is forced to move to Hallowell, Maine, where turmoil follows, and there is no escape. Residents come down with an unexplained illness, some disappear, and others die. Isaac Mayfair is adamant about keeping Adria safe, even from her estranged sister, whom he has warned her to stay away from.
As unspeakable secrets unfold all around Adria, impossible choices become hers to bear. Ultimately, no matter what path she takes, her life and the lives of those she loves will be in peril. As she learns about the werewolf world, she also learns why her place in it will change the destinies of many.