When an acclaimed novelist acquires the summer estate of her youth on Orcas Island, Washington, she voices three intentions: to provide a respite for her hardworking husband; to preserve the innocence of their precocious thirteen-year-old son; and to renovate a cliffside cabin into the writing retreat of her dreams. But there's also an unfulfilled promise that has haunted Meredith Lila Gaines since the day she fled the property and the life she knew.

Her latest bestselling psychological thriller shares its title with the remote manor house, and not for the reasons most think. Frightening rumors have long swirled throughout the San Juan Islands regarding the property, and according to locals, those tales aren't to be taken lightly. Meredith knows this firsthand; it's the reason she's returned for what lies beneath the emerald waves of Rosario Strait . . .