Ketaki and Daksha
Ketaki was the daughter of Daksha Prajapati. She was very beautiful. Because of her beauty and demeanor, she earned lot of fame. This made her arrogant. When her father asked her to get married, She refused saying that she can not find any person worthy of marrying her. So, she decided to spend her entire life under the shelter of Lord Shiva in Himalayas. Accordingly, She went to Himalayas and started her penance.
Curse of Goddess Parvati
Once Goddess Parvati thought of testing her. Parvati disguised as a cow reached the plac ewhere Ketaki was meditating and started bellowing loudly. Ketaki was disturbed so she uttered some foul words for the cow. Hearing this, Goddess Parvati came into her real form and cursed her. She said in your arrogance you can't find any male worth marrying you so you will have to go down to earth and be common wife of five men.
On recognizing Parvati, Ketaki fell in her feet for apology. Parvati said her curse is immutable, but this will be as a blessing in disguise for her. Even after being a common wife of five husbands, your wifely devotion shall remain intact and then realms Parvati left.
Sadness of Ketaki and Indrani's wish
Ketaki was sitting at the bank of Ganga, her tear drops that fell on the water become golden lotus and began to float in the current. Indra spoted them and took few flowers for his wife Indrani. Indrani was delighted to have them. Indrani longed to have more of them and said that the right place of blooming was the pond in the heaven.
Indra sends Gods to find the flower
Indra send Dharamraj to find the origin of the flower. When he didn't return, Indra send Vayu dev behind him. But, when he also failed to return Indra send Ashwini Kumars to find the golden lotus. But after long time when none of them returned Indra decided to go and search himself.
Indra meets Ketaki
Indra found Ketaki sitting on the bank of Ganga. Charmed by her beauty he sought her identity. Ketaki said she is daughter of Daksha Prajapati and she was there to do her penance and meditation. Indra said that meditation and penance are for elderly sage and offered her to marry him and enjoy the pleasure of heaven.
Keatki was hurt by the offer and said your four deites have already suffered the consequence of giving me such offer and if you seek your welfare you should return to your abode.
Ketaki shows helpless gods to Indra
Indra immedately understood that the four deities referred to by her were none else but Dharamraj, Vayu, Ashwini Kumars. When Indra inquired further about them. Ketaki took him to a deep cave where four deities were lying tied down. On seeing them Indra lost temper and said though you pretend to be ascetic, but your heart is full of demonic tendencies. Do you know the consequence of holding them in captive.
Indra meets the protector of Ketaki
Ketaki said, thet they are being held n captive by her protector. Indra found an ascetic with long matted hair lost in meditation in a cave. Indra in arrogance began to utter some foul words for the ascetic. But when the ascetic came in his real form Indra was shocked to see that he he was no one else then Lord Shiva himself.
Lord Shiva curses five Gods
Lord Shiva thundered that Ketaki is like a daughter to him and since Indra and his deities have insulted her so you five have to go down on earth as human being.
Ketaki and Lord Shiva
Lord shiva said that in Dwapar Age, Lord Vishnu will incarnate as human being, at that time you five will also live on earth as human being, and at that time Ketaki shall be your common wife. In this way, your desire to have her shall be satiated and you five will also help Lord Vishnu to establish the rule of righteousness on the earth. This way your curse will fructify as boon to you all.
Thus due to the effect of the collective curse of Lord Shiva and Devi Parvati, Pandavas got Draupadi as a common wife.