Hou I was a good archer who lived in ancient China in the days of Emperor Yau. Apart from his bow, Hou I also had a horse which ran so speedily that even the wind could not catch up with it. One day, he mounted on his horse to go hunting. But his horse ran away. So, Hou I came to Kunlun Mountain and met the Queen-Mother of the Jasper Sea.
And she gave him the herb of immortality. He took the herb home and hid it in his room. But his wife, Tschang O, one day came upon the hidden herb and ate some of it when Hou I was not at home. The herb had a magical effect and Tschang O immediately floated up to the clouds. When she reached the moon, she saw a castle and went in. Since then, she lived in the castle as the Lady of the Moon.