As the story opens, Clay Jannon - a young, unemployed web designer - takes a job at 'Mr. Penumbra's 24-hour bookstore' in San Francisco. This peculiar establishment has a limited number of normal books for sale in front and a large number of unusual books in back which 'members' can borrow. Clay learns that these odd books apparently hold clues to solving some secret which people have been trying to decipher for centuries.
Curious to figure out what's going on with these books Clay enlists the assistance of friends with needed attributes: coding skills, money, access to technology, and so on. Clay's group secretly copies and analyzes a key book which eventually leads them to a secret society in New York that's working toward a very special goal.
The activities of Clay's cadre involve numerous intricate gadgets, fancy coding, high-tech cameras, Google's computers, cross-country travel, breaking and entering, and so on. For me the book started off strong but I lost interest about 2/3 of the way in when the 'fairy tale' aspects of the story took over. Moreover I was disappointed with the book's ending which seemed anti-climactic after the huge build up. I think people interested in high-tech gadgets would find this book interesting but it just wasn't one of my favorites.