Christmas Eve, 1987. A girl named Celeste disappears from the town of Millbrook, Vermont, after following the sound of a bell nobody else can hear. Her sister, Iris, spends the next thirty years tracing that sound to St. Stephen's Well, a forgotten stone spring on the edge of the national forest. What she finds there isn't a body, or a ghost, or a message. It's something that was always waiting for an answer. Luna tells a story of longing, patience, and the shape of a wish made wrong.