Once upon a time...
Far, far in the forest there were two little huts, and in each of them lived a man who was a famous hunter, his wife, and three or four children. Now the children were forbidden to play more than a short distance from the door, as it was known that, away on the other side of the wood near the great river, there dwelt a witch who had a magic ball that she used as a means of stealing children.
Her plan was a very simple one, and had never yet failed. When she wanted a child she just flung her ball in the direction of the child's home, and however far off it might be, the ball was sure to reach it. Then, as soon as the child saw it, the ball would begin rolling slowly back to the witch, just keeping a little ahead of the child, so that he always thought that he could catch it the next minute. But he never did, and, what was more, his parents never saw him again.