Altair and Vega are two stars that can be seen clearly in the summer sky. In Chinese folklore, however, they are related to a romantic story about the granddaughter of the Emperor of Heaven and a poor cowherd.

Niulang, or Cowherd, a young farmer who seeks out a meager living with his old ox. His parents died young and he had to work hard. He was often tired and hungry but always finds time to take care of his old ox.

One day when he returned home, he was amazed to find that his clothes were washed clean and dinner was already on the table. This continues for several days. Niulang was so surprised and becomes determined to find it out. One day, he pretends to be out, but hides behind his cottage. Soon he saw the most beautiful young girl come to his cottage and complete family chores for him. Caught by Niulang, the girl told him her name is Zhinu, literally means weaving girl. She saw him working too hard and would like to help him in some way.

Her kindness was well appreciated. Immediately, Niulang falls in love and asks Zhinu to marry him. Zhinu agrees to marry him and they live a simple, happy life together with their son and daughter.

However, one day, Zhinu was abducted and taken back to heaven. It turns out she's the granddaughter of the emperor of the Heaven. He was infuriated to find her marrying an earthly husband and sends the empress to fetch their disobedient girl.

When Niulang comes home and finds his wife is missing, he and the two kids burst into tears. Suddenly the ox began to talk. He asked Niulang to kill him and dons the cowhide, which will take him to the heaven.  Having no other choice, she did that and the magic power of the cowhide sends him on a chase that enables him to soon catch up with the abducting empress. The Empress takes out her hairpin and swipes it across the sky. It swells into a raging river, separating husband and wife. Their anguish finally moves the emperor, who allows Niulang and Zhinu to meet once a year, on the seventh day of the seventh month, or Qixi.