For as long as she can remember, Addie McKay has had an intense fear of the sea-which made growing up with the Atlantic Ocean as her backyard rather difficult. But something has changed. Lately she has found herself strangely drawn to the ocean. It's as though the sea is casting a spell over her, calling out to her, and she can't help but feel that it coincides with the arrival of the mysterious stranger in town. Addie's never had a reason to step foot in the ocean until one night she's forced to dive into the salty depths. There she makes a startling discovery and exposes a hidden threat looming beneath the surface. Now, Addie knows there is more to her lifelong fear of the water than she ever imagined possible-and that it may be the only thing keeping her from being swept away by the sea.