Bhanumati was not as beautiful as other women, plus her personalities were not great so Duryodone was not really in love with her. Duryodone tried to avoid her as much as he can so Bhanumati would get very upset. One day, Bhanumati went to a Agori who practiced black magic. Bhanumati asked the Agori if there was any way, she can have her husband be crazy about her. The Agori took out water and said a mantra, then told Bhnumati that pour this water on your husband's head and he will be crazy about her, but the water must not spill on the ground.
Bhanumati secretly came to Hastinapur and waited for Duryodone. When Duryodone came, Bhanumati went to greet him and tried to pour the water on his head. But, Duryodone was also a warrior so he stepped out of the way by being alert. The water was spilled on the ground and went all the way to Patal. In Patal, there was a Nag and on top of his head the water landed. The Nag became enchanted and came to the ground where Bhanumati and Duryodone were conversing. Duryodone tried to fight the Nag but the Nag was too strong. The Nag defeated Duryodone easily and tied him up. Then the Nag grabbed Bhanumati and did unspeakable things to her. Everyday, during midnight, the Nag would come and fight and tie Duryodone and grab Bhanumati. Once, the Nag told Duryodone that you are not a great Satya man so you cannot defeat me.
Duryodone thought that who could be the great satya man that can defeat this Nag and help me. Duryodone thought about Bhisma pita, Dorna Acharya, Kripa Acharya and Ashwattama but he did not want to look embarrassed so he couldn't ask them. All of a sudden, Duryodone remembered Karna who could keep this secret and would be able to defeat this Nag. Duryodone went to Karnapur and was greeted by Karna. Even though Duryodone had thrown karna out of Hastinapur, Karna still greeted him warmly.
Karna - Vira, is everything all right for you?
Duryodone - No Vira, things are not good. This Nag does very nasty things to me and my wife. If I tell others that would laugh at me and tell me that I am not strong to handle my own problems. Only you would keep this secret and help me.
Karna- Come, I will come with you and help you.
Duryodone - Vira, come back and take your rightful possession back. I am very sorry to do this to you.
As planned by Karna, Duryodone acted normal during mid night. Karna hid behind one of the great pillar with weapons ready. At mid night, the Nag came and tried to fight with Duryodone. But, this time Karna was there so he came out and challenged the Nag. Both of them fought a very hard battle. The Nag had a boon that only a great Satya man could defeat him. Karna fought hard with a sword pushing the Nag back. The Nag tried to fight against Karna using all kinds of tricks but Karna was too skillful. After few moments, Karna defeated the Nag. The Nag begged for mercy and offered Karna a divya horse that can take him anywhere. The Nag also promised never to come back. Karna let the Nag live on condition that he should never bother Duryodone or his wife again.
Duryodone and Karna became friends again, after this incident.