A young peasant lad is surprised when his ox reveals to him that it is in fact the Ox Star, sent to earth as a punishment. The ox explains that as a reward for his kindness, it will help him get a wife.
The young man is instructed to go and hide himself by a pool nearby, which was bring used by the Heavenly Maidens to bathe in. He hid one of the sets of clothes by the poolside, thus trapping one of the maidens. The young man spoke to her kindly, and she agreed to be his wife. She told him that she was in fact the goddess of weaving. After they were married, they had two children -- a boy and a girl.
The gods were not pleased with the idea of the weaving goddess remaining on earth, and sent messengers down to retrieve her. The ox once more comes to the rescue, telling the man that it would die soon, and that with the oxskin, the man would be able to pursue his wife.
The ox herd set off after his wife, with his two children in baskets slung from a carrying pole across his shoulders. Before he could reach her though, he was spotted by her grandparents, who drew a line in the sky with a hairpin. The line became a raging river between them (Milky Way, with the oxherd Altair, and the weaving maid as Vega). The family was so upset that it was decreed that they could be re-united for one day every year. (Seventh day of the seventh month) On this day, all the magpies fly up and form a bridge across the river and the ox herd goes across and visits his wife.
In another variation, the peasant is challenged to a race, and his wife gives him three objects -- a comb, a glass and a pin, telling him to throw the comb and the glass behind him, and draw a line in the ground with the pin, also behind him. The comb then becomes a forest, the glass a mountain, but the young man draws a line in the ground ahead of himself, and separates himself from his wife with a river.
The festival celebrated on this day is one where young girls pray to the weaving goddess to give them skills in embroidery, spinning, etc.