During their one year stay in disguise in Viratnagar, all the Pandavas had taken different guise and were engaged in different tasks. Arjuna had taken the guise of an eunuch Brihannala and begun to train Uttara the daughter of the king Virat in dancing and music. Uttara always regarded Arjuna as her teacher and Arjuna too taught her music affectionately regarding her as his daughter.

Towards the end of the Pandavas' unknown stay, Kauravas had attacked the kingdom of Virat. Prince Uttar then went to repulse the attack. But seeing the formidable Kaurava warriors like Bheeshma, Karna, Dronacharya and Kripacharaya, he began to retreat in panic. In the guise of Brihannala, Arjuna was driving his chariot. He stopped his chariot and asked Uttar to drive the chariot. Arjuna then defeated the Kaurava army. Yudhisthir was staying in the king Virat's court as the courtier Kank. His duty was to muse the king in the game of dice. Hearing the news of Kauravas' defeat, he began to praise Brihannala. Annoyed by it, the king Virat threw the dice at Kank's face. Kank's nose began to bleed. Meanwhile, Draupadi who was in the guise of Sairandhri, came running and collected the blood in a bowl thus preventing it from falling on the ground. Prince Uttar too arrived in the court and intimated his father about the happenings. Only then, the reality of the Pandavas was revealed to the king. He at once begged pardon of Yudhisthir for hitting him with the dice.

Once the reality of the Pandavas was fully revealed, the king Virat felt sorry for the way in which they were treated for the past one year. With the purpose of converting their brief stay into an eternal friendship, the king Virat proposed to marry his daughter, princess Uttara to Arjuna. With lot of seriousness, Arjuna replied that as he had trained Uttara in dancing and music, he now regarded her as his own daughter. Princess Uttara too had regarded him as a venerable teacher. "So to avert every kind of public slander, I propose to accept her as the wife of my son, Abhimanyu. It would be a matter of pride for you also to have the son of Lord Krishna's sister Subhadra as your son-in-law", said Arjuna.

Thereafter at an auspicious time, princess Uttara got married to Abhimanyu. In the fierce battle of Mahabharat, Guru Drona had arranged a Chakravyuha (a circular array of the forces). As Arjuna was the only warrior on the Pandavas' side to break into the Chakravyuha, the Kauravas had drawn him away under a preplanned strategy. Their aim was to capture Yudhishthir. Abhimanyu too knew how to break into the Chakravyuha but he did not know how to come out of it. The other Pandavas had assured him of help if he broke into the Vyuha. Abhimanyu did the same but Jayadrath, the brother-in-law of the Kauravas stopped other Pandavas from entering the Vyuha. Jayadrath had the boon of valour for one day from Lord Shankar. That boon showed its full effect on that day. Inside the Vyuha, Abhimanyu fought valiantly. He even defeated the veterans of the Kauravas side. But at last fighting together, they overpowered Abhimanyu and killed him when he was rendered armless. Uttara was expecting an issue then. She was eager to be Sati (commit self-immolation) with her dead husband. But convincing her in different ways, Lord Krishna saved her from committing self-immolation.

Indignant of his father's killing, Ashwatthama had sworn to destroy the Pandavas. At the end of the Mahabharat battle, he had killed five sons of Pandavas. To kill the unborn baby of Uttara, Dronaputra Ashwatthama launched Brahmastra. Seeing the Brahmastra coming towards her, Uttara prayed to Lord Krishna to save her baby: "O Lord of the three worlds. Save me. This all-destroying Brahmastra is coming towards me. It is set to destroy my unborn baby who is the last and only momento of my dead husband. O Lord, save my baby". Lord Krishna was then about to board the chariot. At the same time Uttara arrived at His refuge, perplexed. The Pandavas also saw that five ignited arrows were coming towards them.

"Don't be afraid", saying this Lord Krishna cut the five ignited arrows with His wheel (Sudarshan chakra). Since He had promised to save Uttara's unborn baby, He assumed a micro form and entered Uttara's womb. There He saved the baby from the deadly Brahmastra. Thereafter Krishna's departure for Dwarka was postponed till the birth of Uttara's child.

Lord Krishna had protected the baby from the impact of Brahmastra by moving his mace around it. But the impact of Brahmastra lasted till its birth. So, the baby became virtually lifeless soon after his birth. Hearing the news, Lord Krishna came running. On the way, He scolded Ashwatthama: "Scoundrel, even if your Brahmastra succeeds to kill the baby, I will resurrect him". Kunti too met Krishna on the way. She too prayed to Krishna to resurrect the baby. Subhadra too prayed for the baby's resurrection. It was Draupadi who informed Uttara of Lord Krishna's arrival. Hurriedly, Uttara arranged her clothes and lay flat at the feet of Lord Krishna. She was wailing bitterly. Then, taking the lifeless baby in her lap, she said: "O son, the Lord of all the three worlds is standing before you. You are the son of a religious father. Such impoliteness is not good for you. Greet God of all gods. See, His auspicious face. I was thinking earlier that as soon as you took birth, I would put your hand at His feet. But you have destroyed even that hope of mine".

Seeing the condition of Uttara, Lord Krishna took some water in His palm and quenched the Brahmastra saying: "If I have had true love in religion and Brahmins, may this baby come to life. If I have continuously followed the truth and religion, may this son of Abhimanyu come to life. If I had preserved the religion by killing Kans and had not perpetuated jealousy in heart, may this baby which has died due to the Brahmastra come to life".

As soon as Lord Krishna uttered these words, the baby opened his eyes. Everyone present there was moved with joy. In later course, that baby came to be known as Parikshit. Since Vishnu saved him, one of his names was also Vishnu.