Nobody has managed to topple Einstein's theory of relativity, even though it leads to the shocking conclusion that most of the universe must be made of a mysterious form of invisible matter that nobody has observed. Now physics stands at a crossroads. Some of the sharpest brains in physics have dedicated their lives to search for this "dark matter" while others are working on a new theory of gravity. Chasing Einstein follows leading scientists around the world, and to the edge of the universe.