From the New York Times best-selling author of The Southern Book Club's Guide to Slaying Vampires, this unholy hybrid of Beaches and The Exorcist blends teen angst and unspeakable horrors into a pulse-pounding supernatural thriller.The year is 1988. High school sophomores Abby and Gretchen have been best friends since fourth grade. But after an evening of skinny-dipping goes disastrously wrong, Gretchen begins to act…different. She’s moody. She’s irritable. And bizarre incide