Answer: to a family of trolls
While the two princesses are playing, Elsa creates piles of snow as Anna jumps onto them. But, Anna begins to jump faster than Elsa can make the snow. When Anna starts to fall, Elsa accidentally hits her in the head with her power causing her to fall unconscious and a strand of her hair to turn white. Elsa then wakes her parents to help her. After consulting a book, the king and queen take their two daughters to a family of trolls in the forest. The leader of the trolls, the Grand Pabbie, tells them that Elsa must be locked away from people to keep her and others safe. He also alters Anna's memory so she cannot remember Elsa's magic.