In short:
Bruun is the teddybear of Rietje and taken by her brothers to play a wild game with it.
Bruun ends sitting on a pole in the water. Rietje is sad and misses the bear.
A fisherman finds the bear and gives it to a bunch of boys that wreck the bear.
Rietjes' brothers take the bear back and put it in Rietjes' bed.
Her mom sees the bear and repairs it. When Rietje awakes, she sees the bear and is happy again!