Richard Hammond spends this episode tracking down animals and people whose senses work in ways that seem to break the rules. Elephants pick up rumbles through solid rock and feel them travel up through their feet, a form of long-distance communication that has nothing to do with hearing in the usual sense. Seals use their whiskers to read the wake left behind by a fish that swam past seconds earlier, letting them hunt in total darkness. Hammond then turns to people, meeting a blind cyclist who navigates a mountain bike trail by echolocation, using clicks and the sound bouncing off obstacles the way bats do, guided in part by comparisons to actual fruit bats. Along the way he talks with the researchers who study these abilities and tests some of the sensing techniques himself, treating each case as a working system rather than a curiosity. The episode's throughline is simple: senses humans barely notice, like touch or hearing, get pushed by evolution and training into something close to a superpower.