Lucia Blackwood was warned never to return to Bellwether Island. When she inherits Blackwood House, she finds it waiting with a light in the window and a man who knows her name. Beneath the house are seven locked rooms that only open at different tides. The first tide has already opened, and something inside is calling her in her mother's voice. Her mother was supposed to be dead. On Bellwether, the sea doesn't let go.