There used to be a short play called. Xiaosan is a fairy in the sky.

That short play is called extraordinary mother-in-law I didn't give a perfunctory answer. In fact, I thought about it. First of all, according to what you said, "mistress is a fairy girl in the sky", I can tell you responsibly that there are many TV dramas that meet this situation, such as "Fairy Couple" and "Cowherd and Weaver Girl" ... However, there is another key word in your question, and that is "short play". It is because of this word that I have determined the answer. The Hong Kong drama Extraordinary Mother-in-law, also known as My Mother-in-law is not a human being, has only 20 episodes, which meets your requirements. Besides, that woman is indeed a fairy in the sky. To be exact, her name is Wei Zi.