Darkfever ~ Karen Marie Moning

This is the first book in a new series, the Dark Series. Mackayla Lane, Mac, grew up in small town Georgia, with her sister, Alina. Now Alina, who was at school in Dublin, is dead, and no one knows why or who did it. Mac is determined to find some answers. Along the way she encounters Jericho Barrons, who knows something about the community that Alaina had become involved in, and may end up keeping Mac alive.