Librarian Anne Adams has found the perfect escape: a job cataloguing the library of Winterbourne, an architectural masterpiece on a remote island off the west coast of Scotland. Surrounded by an awe-inspiring landscape, the library is magnificent, with priceless first editions, a librarian's dream. However, Anne's early weeks in her new job are beset by obstacles - no internet, a house plunged into darkness every night and unexplained mysteries on the island. After weeks of isolation, upon meeting the mysterious owner Lucien Broussard, Anne is puzzled. Eloquent and well-travelled, his reclusive nature seems uncharacteristic. But after finding a cryptic clue within the pages of a book, Anne discovers that Broussard's collection includes everything from the mundane to the books no one should ever open . . .