The Katha Upanishad tells the story of a young boy, Nachiketa, son of the sage Vajasravasa. Nachiketa is witnessing his father donate all his possessions in an act of penance, and in a spirit of youthful inquiry, repeatedly asks to whom he was to be donated. Angered by the boy's questioning, his father exclaims "I give you to death!"
To stay true to his father's word, the boy departs to the abode of Yama, the God of death. Upon arriving, he patiently waits three days for Yama to return. His sincerity is rewarded by Yama with three wishes, one for each day he was kept waiting.
His first wish is for his father to be happy upon seeing his return. His second wish is to learn a fire sacrifice that provides passage to heaven, which is explained to him and named the Nachiketa sacrifice in his honor. His third wish is simple - "I would like to know what happens after death."
Yama attempts to dissuade him by offering wealth, pleasures, and power. Undeterred, Yama goes on to paint a detailed portrait of the subtle nature of reality according to Brahmanic philosophy. Many of the verses and concepts of the Katha Upanishad can be found in the Bhagavad Gita.
