With their beloved mother only a few days to live, her children decide to give her a surprising parting gift: bring Dave, a lifelong fan, to her bedside in the Ardennes. But even though everyone adores her, brothers, sister and brother-in-law are not on the best of terms and cooperation is not their strong point. For her sake, however, they will overcome their resentments, drawing from their love the energy and the madness necessary to carry out their project. Finding Dave and luring him to the Ardennes will be no easy task.

Thirteen-year-old Bastien is the center of a reconstructed family: six half-brothers and sisters, eight "parents," and as many houses. His tasks within the family are far more complex than what he has to do at school. But enough's enough: the children decide to wage a revolution and turn the rules upside down. All together, they squat a large apartment and now it'll be up to the parents to come to them!

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.”