Ronia is the daughter of Matt the robber, and she lives in a stone keep high on a hilltop in Matt's forest. The night she was born a lightning strike broke the keep into two halves, with a terrible gulf between them. One lean season when Ronia is 9 or 10, a gang of rival robbers move in to the other half of the keep- including another child, Birk, is the same age as Ronia. They begin encountering each other in the forest and after they each save the other's life more than once, they become fast friends. But the woods are full of harpies, trolls, and sheriff's men. If the two gangs of robbers can't figure out how to set aside their differences, neither of them will last the long winters yet to come. This is one of my absolute favorites from childhood, but I had never read it before as an adult. It stands the test of time!