From the New York Times best-selling author of The Southern Book Club's Guide to Slaying Vampires comes an unholy hybrid of Beaches and The Exorcist that blends teen angst, adolescent drama, unspeakable horrors, and a mix of '80s pop songs 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…differe...