Sixteen-year-old Mara Westray has just lost her mother, and now, being shipped off to live with the father she doesn't know is not how she imagined grieving. She's already counting down the days until she turns eighteen and can leave the tiny island of Swans Landing.

But from the moment she steps off the ferry, nothing is as ordinary as it looks. Whispers of a haunting song on the wind make her see impossible things, and she isn't sure she can trust her judgment about what is real and what isn't anymore. Maybe she can't even trust her judgment about quiet Josh Canavan, whose way of speaking in riddles and half-truths only confuses her more, luring her deeper into the secrets hidden beneath the ocean's surface.

As she tries to unravel the events that led to her mom fleeing the island sixteen years ago, Mara finds that the biggest secret of all is only the beginning.