Seventeen-year-old Vanessa Sands is afraid of everything—the dark, heights, the ocean—but her fearless older sister, Justine, has always been there to coach her through every challenge. That is, until Justine goes cliff-diving one night near the family’s vacation house in Maine, and her lifeless body washes up on shore the next day.
Though her parents hope that they’ll be able to find closure back in Boston, Vanessa can’t help feeling that her sister’s death wasn’t an accident. After discovering that Justine was keeping a lot of secrets, Vanessa returns to Winter Harbor, hoping that Justine’s boyfriend might know more. But Caleb has been missing since Justine’s death.
Soon, it’s not just Vanessa who’s afraid. All of Winter Harbor is abuzz with anxiety when another body washes ashore, and panic sets in when the small town becomes host to a string of fatal, water-related accidents in which all the victims are found, horrifically, grinning from ear to ear.
Vanessa turns to Caleb’s brother, Simon, for help, and begins to find herself drawn to him. As the pair tries to understand the sudden rash of creepy drownings, Vanessa uncovers a secret that threatens her new romance—and will change her life forever.