Theory:

The lesson "An Alien Hand" is written by Jayant Narlikar. The lesson narrates the story of Tilloo, a boy who lives beneath a planet's surface and his desire to learn more about an underground passage through which his father usually goes to work.
 
Some of the characters of the lesson are,
  • Tilloo
  • Tilloo's father
  • Tilloo's mother
  • Defence man
  • Scientist
  • Social scientist
  • President
  • Security staff
  • People from NASA
  • Narrator