Black holes are, by definition, invisible: nothing that falls in comes back out, not even light. This Horizon film follows the international team behind the Event Horizon Telescope, astronomers linking radio dishes across the globe into a single virtual instrument to attempt the first actual image of one, and the theoretical physicists trying to square general relativity with what such an image might show. The film explains why the project targets a supermassive black hole at the center of a galaxy rather than a smaller stellar one, since a bigger event horizon is paradoxically easier to resolve from Earth. Interviews with researchers on the project lay out the technical hurdles: synchronizing data from telescopes on different continents to the nanosecond, then waiting months for the results to be processed and compared. The program treats the imaging attempt as a test of Einstein's equations themselves, since a picture that matched no prediction would force a rewrite of the physics. It ends with the data still being analyzed, the picture not yet confirmed.