The katha
Parvati, daughter of the mountain king Himavan, had set her heart on Shiva from childhood. In the Himalaya she did a long and severe penance for him, living on leaves, then on air, through heat and cold, until her father grew anxious for her. Then Narada came to Himavan and said that Vishnu wished to marry his daughter. Himavan, delighted, agreed.
When Parvati heard this she was heartbroken, for she would have no one but Shiva. She told her friends, who carried her away (harat) secretly into a dense forest and hid her in a cave, so that she could not be given to Vishnu. There, on the third day of the bright half of Bhadrapada, under the Hasta nakshatra, she made a linga of sand and worshipped it, fasting without food or water and keeping awake all night singing Shiva's praises.
Moved by her devotion, Shiva appeared and promised to make her his wife. The next morning Parvati broke her fast and immersed the linga. Himavan, searching for his daughter, found her in the forest, and when she told him her vow he agreed to give her to Shiva, and the two were married.
Shiva tells Parvati that any woman who keeps this fast with devotion will, like her, be blessed with the husband of her heart and an unbroken married life.