Gravitational waves, first predicted by Einstein a century ago, are ripples in spacetime caused by cataclysmic events such as colliding black holes. This film follows the Laser Interferometer Gravitational-Wave Observatory, the instrument built to detect those ripples after they cross the cosmos and arrive on Earth as impossibly faint distortions. It traces the decades of theoretical prediction that came before any device existed sensitive enough to measure them, and the engineering problem of building a detector precise enough to register a change smaller than the width of a proton. The film explains what a black hole collision actually produces in terms of signal, and how scientists confirm that a detected ripple came from deep space rather than local noise. It is a straightforward account of a scientific instrument and the physics it was built to confirm, aimed at viewers curious about how astronomers can hear an event that produced no light at all.