The Upanishad uses as its base the story of Vajashravasa (वाजश्रवसः), which was first mentioned in the Rigveda (10. 135), and also in the Taittiriya Brahmana (3.1.8), and later the Mahabharata (Anusasana Parva 106). vAja-shravasaH वाजश्रवसः means descendant of vAja-shravA वाजश्रवा. vAja-shravA was the name of a sage, as well as means 'one who is famous (-shravA) for his charity of giving grains (vAja-)', implying the great sage arUNa अरुण . uddAlaka उद्दालक was the son of aruNa, and he performs a sacrifice in which he was required to give away all his worldly possessions. His son Nachiketa नचिकेता saw that the cows given were all who had 'drank-their-last-water' (पीतोदकाः), 'eaten-their-last-grass' (जग्धतृणाः), 'milched-for-last' (दुग्धदोहाः), 'whose senses had been diminished' (by old age) (निरिन्द्रियाः). Such charity was not going to give his father any merits. Feeling disturbed by the inappropriateness of his father's observance of the sacrifice, Nachiketa asks to whom was he given (since he too was a possession of the Rishi and hence needed to be given away). The sage ignores him twice, but on third asking, the irritated sage said in anger, "Unto Yama, I give thee.", whereupon Naciketas goes to the abode of Yama, and, finding him absent, waits there for three days and nights. Yama on his return, offers to grant him three wishes. (1.1.9) Naciketas wishes the following: to be allowed to return to his father alive, and that his father not be angry with him (1.1.10); to be instructed as to the proper performance of Vedic fire-sacrifice in order to gain immortality (1.1.12–13); to be given knowledge about life after death (1.1.20). Yama grants the first wish immediately (1.1.11). In answer to Naciketa's second question, Yama expounds the performance of a special fire-sacrifice, which he states is to be named after Naciketa (1.1.15–19). "He who knows the three-fold Naciketa-fire and performs the Naciketa fire-sacrifice with three-fold knowledge, having cast off the fetters of death and being beyond grief, he rejoices in the realm of heaven." (1.1.19, trans. Paramananda) Before answering the third question, Yama tests Nachiketa, offering him all sorts of worldly pleasures instead, but Naciketas insists (1.1.21–29). The remainder of the text (parts 1.2 to 2.3) contains Yama's teaching concerning true immortality.