Yayati, a virile man before he was cursed by Sukracharya, desperately wanted to regain his youth. He called his five young sons to him and begged them to swap their youth for his kingdom.
``Your grandfather's curse has made an old man,'' he said to them, ``but I have not had my fill of the joys of life. If one of you will bear this burden of my old age, I shall give him the rule of my kingdom.''
The eldest son refused saying that he would be mocked mercilessly were he to take his father's old age.
The second son refused because old age would destroy not only his strength but also his wisdom.
The third son refused saying that an old man could not get about from one place to another.
The fourth son too refused. He did not want the ignominy of having to be cleaned and taken care of by other people.
Finally, Yayati approached his fifth, and youngest son, Puru. Puru, awash with filial love, agreed to take on Yayati's age. Yayati, suddenly made younger, retreated to the garden of Kubera and spent many years with beautiful women and charming apsaras. Meanwhile, Puru ruled the kingdom with restraint and wisdom.
Finally, Yayati realized that his sexual desire could never be quenched, much as a fire could never be quenched by the addition of ghee. He returned to Hastinapura and took back his old age from Puru. Puru, restored to his youth, continued to rule Hastinapura and brought great renown to the Bharata race.