Young people seamlessly weave into the fabric of nature, swim in crystalline lakes and revel in the calm presence of the ancient trees. But this idyllic harmony is imperilled as the forest faces man-made extinction. Driven by her love for the forest, 22-year-old Ida becomes the leader of the new Forest Movement, coming face to face with industry giants and confronting generational bias. Unfolding as a modern fairy tale in the enchanting embrace of the Finnish forest, Once Upon a Time in a Forest is a hopeful ode to nature and its protectors.