Oxford and the circles within circles there make up the background for the strange activities of ""the watcher"" whose prey is Dr. Marion Manning, whose husband had died on a scientific expedition; and young Ezra, deep in Anglo-Saxon literature, and Rachel become involved in her haunting. Her companion, Joyo, has her ways of complicating the situation; the watcher is killed; poisonous henbane is loosed and the complexities of a dual personality are revealed. Brainy.