The first hints that there might be more out there than meets the eye emerged from the gloom in 1846 with the discovery of the planet Neptune. In the middle of the 20th century scientists discovered dark matter and in the late 1990s dark energy. Jim explores the quest to uncover the nature of dark energy and to see dark matter pull the first stars and galaxies together, a quest that involves peering into the darkest period in the cosmos's past.