Two rival forest bandit clans, the Mattis and the Borkas, fight each other for treasure from their victims and divide the forest in two. On a stormy night Ronja is born to Mattis, leader of the bandits of the forest castle and his wife Lovis; on the same day the castle is split in two by a lightning bolt, creating "Hell's Gap." Mattis, ecstatic about his daughter, calls Ronja the clan's greatest treasure.