Living Incognito
Thus, the twelve-year period of exile was about to end. Pandavs decided to pass the last additional (thirteenth) year incognito, as decreed, in the capital city of the King Virat. For this purpose, lest they should be detected, Pandavs disguised themselves as follows:

Yudhisthir -- As he was well-versed with both the scriptures and skills of dice, rules and functioning of royal court, Yudhisthir decided to serve the king in the capacity of his adviser and priest. He assumed the name as Kankanbhata.

Bhim - His mighty and huge body required much food to satisfy his appetite. Therefore, Bhim decided to work in the Royal kitchen as the chief cook assuming the name of Ballava.

Arjun - Arjun was destined to pass one year as eunuch (thanks to the curse of Urvashi of Heaven). Therefore, it was decided that he teach dance and music to the princess Uttara in the guise of eunuch assuming the name Brihnnal.

Nakul became Granthic, the caretaker and guard to the horse stable as he was expert in the training and treatment of horses.

Sahadev was in charge of cow-sheds and was called as Tantipal.

Draupadi was appointed as the chief maid-servant to the queen. She was to be known as Sairandhri.

Thus, separately, without letting others know that they were related, all the Pandavs entered into the service of the King Virat in the hope that the agents of Kauravas would not be able to spot them and inform Duryodhan about their hide out.

Story of Prince Keechak

Keechak was the grown up prince of the kingdom. King Virat had decided to hand over the reign of his kingdom to this son sooner than later. Keechak was powerful and lustful. He was attracted towards the beauty and youthfulness of Draupadi ('Sairandhri'), the maid-servant of his mother.

He started making passes at her and instructed his attendants to tell Draupadi to bring food and drinks to his room.

Draupadi was aware of his evil nature. Secretly she told the powerful Bhim about Keechak and his overtures. The angered Bhim told her to accept Keechak's invitation to go his room that night. Keechak was blinded with lust and drinks. He waited that night for Draupadi to come to his room. But instead Bhim went with the glass of milk for Keechak dressed in lady's attire like Draupadi!

The ensuing fight between Bhim and Keechak was very intense as both were equally powerful. Bhim in the end prevailed and Keechak was killed.

King Virat came to know all about the sad end to his ignoble son. He was particularly displeased with his son because he tried to take undue advantage of a maid.

Death of such a disgraceful son, in fact, did not hurt the king in any way. He kept the matter within himself by announcing that his son prince Keechak would be away from the capital for a few months. In fact, King Virat fought on the side of Pandavs in the war.