Ben Underwood lost both eyes to retinal cancer before his third birthday, and by his teens he could ride a bike, play basketball, and navigate his neighborhood without a cane. This episode of the Extraordinary People series follows him doing it: clicking his tongue and reading the echoes that bounce back off cars, walls, and furniture to build a working map of the space around him, the same principle bats and dolphins use to hunt in the dark. Cameras follow him through ordinary routines, skating, walking through his house, moving around other kids, while his family and the people who know him describe how he taught himself the technique on his own rather than through any formal program. The film treats his skill plainly, as a skill, showing the trial and error behind it rather than framing it as a miracle. It stays close to the mechanics of what he does and how he does it, letting the footage of him moving confidently through unfamiliar rooms make the case on its own.