Michael Pollan builds the film around a simple reversal: instead of asking what humans have done to plants, he asks what plants have done to us, using four species that shaped his argument. The apple's story runs through John Chapman, the real Johnny Appleseed, who spread trees across the Ohio Valley not for eating but for hard cider, since sweetness came later through grafting. Tulips get traced back to Dutch speculation in the 1600s, when a single rare bulb could trade for the price of a house. Marijuana growers describe decades of indoor breeding that pushed THC levels far past anything available in the 1960s, done partly in response to prohibition itself. Potatoes anchor the darkest chapter, showing how Ireland's dependence on one variety turned a crop failure into a famine, and how Idaho farms now depend on a handful of clones bred for uniformity. Pollan interviews farmers, breeders, and historians throughout, treating each plant as a strategist that recruited human desire to spread itself across the planet.