In a world much like our own, outside a city cloaked in smog, an adventurous girl slips away from home. Shedding her protective mask, she finds comfort in the shadowy forest and momentarily forgets about her sick sibling and anxious parents. They have warned her against going into the woods, which are supposedly guarded by a ravenous witch. One day, a wise old woman appears and warns the girl against disturbing a dead bird lying on the forest floor. Instead of fleeing from the legendary Witch of the Woods, the girl follows her home and finds that the crone has started a seed bank in an old sewage tunnel. With one magical seed, the crone opens the girl's eyes to the wondrous biodiversity that once made the forest thrive.