On a windswept beach on the Isle of Mull, Cas Longmore is walking away loneliness when she unearths a mystery in the sand. To Cas, torn between Scotland and her New Zealand home, the object seems as odd and out-of-place as herself. Intrigued, she begins to search for its origins, thinking it will bring a brief respite from isolation. Instead, the Calgary chess piece opens the door to friendships and new hope. Her son, meanwhile, brings home his own revelation to shake her world.