Perfume is chemistry, but the people who make it talk about it like memory and desire, and this three-part BBC series follows three noses to see how that works in practice. Jean-Claude Ellena, in-house perfumer at Hermès, works out of a studio in the woods, sniffing and revising as he builds a fragrance meant to evoke a secret garden. Christopher Brosius, an American perfumer with a punk streak, chases scents that pull specific memories out of specific smells, the green sting of tomato leaves, the dust of an old book. Jean Guichard runs the Paris school that trains noses from scratch, and the film sits in on his search for students with the right instinct, a search he compares to finding astronauts: there are fewer working perfumers than there are people who have been to space. Across the three episodes the series treats smell as a technical skill and a form of storytelling at once, watching each perfumer chase the same goal by completely different methods.