To help Francis Hallé in his fight to save the last tropical forests, a documentary filmmaker with a passion for nature decides to make his first film: "The Botanist", an ecological thriller with Leonardo DiCaprio. He traces his path with malice, obstinacy, and discovers, with candor, the arcana of the seventh art. Even if he never gives up, will his film ever exist?

With Once Upon a Forest, Luc Jacquet invites the spectator into a never-before-seen world of natural wonder and staggering beauty. “For the first time, we will be able to watch a rain forest growing before our eyes…Only cinema can offer this unique voyage into a completely untamed universe, a world of perfect balance in which each living thing – from the smallest to the largest – plays an essential role. The film will deliver a complete sensory immersion in the primaeval splendor of one of nature’s richest mysteries, inviting the audience to enter, discover and marvel at a universe of untold treasures while joining its voice to the ever-growing awareness of the need to preserve our world.”

14-part special in which botanist Francis Hallé explains forest science and processes. Part of the "Once Upon a Forest" physical release.