It's the holy grail of physics - the search for ultimate law and order in the universe. And in the last few years, excitement has grown among scientists as they've pursued a revolutionary new approach to unifying nature's forces. It's called string theory and, to the uninitiated, it's totally mind-boggling. But physicist Brian Greene has a rare gift for conveying physics in vivid everyday images, a gift that has turned his recent book The Elegant Universe into a mighty bestseller, and now Greene brings his talent and vitality to this documentary.