Richard Hammond journeys into the parallel universe that lies beyond the limits of the naked eye. Using state-of-the-art imaging technologies, Richard discovers that it's as much the things we cannot see as those we can that shape our lives. From spectacular natural phenomena such as vast, superfast lightning clusters, to one of the wonders of the living world and our own technological achievements, such as the awe inspiring aerial work conducted on high-voltage power lines, Richard explores the hidden secrets of three distinct invisible realms that lie beyond the limits of human vision, helping us to unravel some of the mysteries of our world. Episode 1: Speed Limits Episode 2: Out of Sight Episode 3: Off the Scale