Ronia, the Robber's Daughter tells the thrilling adventure of Ronia, born during a thunderstorm in Matt's castle amidst a band of robbers. The castle, located over the mountain, buzzes with joy for the spirited little black-haired daughter. As Ronia grows, she learns to dance and yell with the robbers, finding her true solace alone in the forest.

Her life takes a turn when she befriends Birk, the son of Matt's arch-enemy. Their friendship ignites the worst quarrel ever between the rival bands, placing Ronia and Birk right in the middle of it. Through their adventures, Ronia and Birk explore the magical forest, learning about friendship, bravery, and the challenge of standing up for what they believe in.