ET Decodes Dan Brown's 'The Lost Symbol'

Dan Brown’s highly anticipated new Robert Langdon thriller, The Lost Symbol, hit stores today and it's already flying off the shelves! Our own Mary Hart sat down for a one-on-one with the bestselling The Da Vinci Code author to get to the bottom of his latest mystery Mystery is the key word, as Dan has kept the plot details under extremely tight wraps until today's release. "You want your readers to experience the book with a clean slate," he tells Mary. "You don't want people to have told them how it ends or what some of the secrets are, and there are a lot of people who wanted advanced copies of this book and there was a lot of pressure to keep it very, very secret." What we can say is that the action of The Lost Symbol takes place in Washington D.C. and it centers on the Freemasons, a real but mysterious society that reputedly included George Washington as a member. A severed hand is one of the clues, but that's all we'll give away. So, how much of the story is fact and how much is fiction?