A terrible accident brings sixteen-year-old Casey Everett's life to a halt—literally. Pronounced dead on the beach during the year-end harbor party, Casey’s sudden return to the living is shadowed by the drowning of her best friend, Liddy. Eager to avoid the rumors that follow her, Casey returns home for the summer, only to find that Liddy won’t let her go. A series of violent nightmares and soulless whispers threaten to drive her mad, but when she watches a boy fall from the sky, she suspects she’s actually crossed that line. That is until Red—an angel fallen to earth to regain his wings—takes her to Limbo: a place that exists somewhere between the living and the dead. Now, in order to save her best friend, Casey must learn to walk these mysterious and dangerous paths or else risk losing Liddy to something worse than death.