Piecing together information from secret sources and a two-hundred-year evolution of the White House, investigative journalists and government insiders weigh in on the mystery of an unusual white box and a top-secret construction project dubbed the "Big Dig" that took place outside of the West Wing from 2007-2012. Using little known images, previously classified material and detailed graphics, the search for truth reveals not only what secrets might lay below the White House, but how their existence could affect democracy as we know it.