In the night when Ronja, the daughter of the robber captain Mattis, was born, a violent storm rolled over the Mattis forest. So scary that only the terrible wild druds might be out there. Lightning cut through the pitch-black sky - and suddenly a gigantic lightning bolt struck and splits the mighty Mattisburg in the middle.Despite this dramatic reception, Ronja grows up into a fairly peaceful little robber girl. But she is brave, and when she is old enough, she is sent to the Mattis Forest to learn about the dangers that lurk there: the gray gnomes and rumble goblins, the dangerous river and the horrible Hellmouth. But even Mattis doesn't know the greatest danger - there's also Birk in the forest, the son of Mattis' arch-enemy Borka... And Mattis had thought that the Borka clan would die out soon! The fact that Borka and his gang of robbers have taken up residence in the part of the castle on the other side of the Hellmouth doesn't make things any better. The old feud between the clans flares up again, and to the chagrin of the two leaders, their children refuse to take part. Instead, they secretly become best friends, and when it comes to light, they are rejected by their fathers.