Leonard Middlebrook, a young attorney with, among other things, a bibliographical interest, accepts an invitation to lonely Ravensdene Court on the Northumbrian coast. There, Francis Raven, the owner, recently retired to the family property after an Indian career, finds himself in possession of an enormous number of old books and other items, and needs help in evaluating them. The attorney, though a man of quiet life -- even dull, as he puts it -- finds himself suddenly at the center of a darkening mystery that stretches from the British Isles to the Far East, and eventually threatens not only him but also the young and spirited Miss Raven, Francis’s niece.