She went home and waited till the next full moon had come. Then, as soon as it was dark, she went along through the wood until she came to the place, and there she crept close to the white birch-tree and waited.
Presently she heard Fair Brother's voice come faintly out of the heart of the tree: "White Birch, it is the full moon and the hour in which Little Sister gave life to my feet. For one hour give me leave to go, that I may run home and look at her while she sleeps. I will not stop or speak, and I promise you that I will return."
Then she heard the voice of White Birch answer grudgingly: "It is her hour and I cannot hold you, therefore you may go. Only when you come again I will beat you."
Then the tree opened a little way, and Fair Brother ran out. He ran so quickly in his eager haste that Little Sister had not time to catch him, and she did not dare to call aloud. "I must make sure," she said to herself, "before he comes back. To-night White Birch will have to let him go."
So she gathered as many dry pieces of wood as she could find, and made them into a pile near at hand; and setting them alight, she soon had a brisk fire burning.
Before long she heard the sound of feet in the brushwood, and there came Fair Brother, running as hard as he could go, with the breath sobbing in and out of his body.
Little Sister sprang out to meet him, but as soon as he saw her he beat with his hands and feet against the tree, crying, "White Birch, White Birch, lift the latch up, or she will catch me!"
But before the tree could open Little Sister had caught hold of the birch shoes, and pulled them off his feet, and running towards the fire she thrust them into the red heart of the embers.
The white birch shivered from head to foot, and broke into lamentable shrieks. The witch thrust her head out of the tree, crying, "Don't, don't! You are burning my skin! Oh, cruel! how you are burning me!"
"I have not burned you enough yet," cried Little Sister; and raking the burning sticks and faggots over the ground, she heaped them round the foot of the white birch-tree, whipping the flames to make them leap high.