A modified 747 called SOFIA climbs to 41,000 feet carrying a telescope built to catch infrared light that never reaches the ground, and this Horizon episode follows the astronomers who fly with it. The film explains why a billion-dollar airborne observatory beats a ground-based one for certain wavelengths, then widens out to other extreme instruments chasing the same invisible universe: a neutrino detector buried deep in Antarctic ice, and observatories built to catch light bent and stretched by black holes. Scientists talk through what they are actually trying to see, from the birth of stars hidden inside dust clouds to signals that might explain how the universe evolved. The episode moves between cockpit and control room footage, interviews with the researchers running these projects, and explanations of the physics that makes each detector necessary. It is a tour of how far astronomers now have to go, literally into the stratosphere and under the ice, just to collect light and particles that ordinary telescopes cannot touch.