Ronja, the only child of a bandit chief, grows up among a clan of robbers living in a castle in the woodlands of early-Medieval Scandinavia. When Ronja grows old enough she ventures into the forest, exploring and discovering its wonders and dangers like the mystical creatures that dwell there. She learns to live in the forest through her own strength, with the occasional rescue by her parents. Ronja's life begins to change, however, when she happens upon a boy her own age named Birk, who turns out to be the son of the rival clan chief.