This episode covers the marriage of the three princes Dhritarastra, Pandu and Vidura. Here's the map I promised of India during the time of the Mahabharata. What's important to notice is that first, the Kuru nation was in a very central location and must have been very important in the politics of the age. The Himalaya mountains acted as an enormous bulwark, keeping each kingdom safe from attack from the north. Thus the marriage alliances seemingly secured peace with neighbors to the west and south, and Pandu was able to wage a military campaign against the kingdoms dowstream along the Ganges to the east.
It is interesting how Pandu eventually thought of his natural father and tried to convert to a Brahmin later in life, giving up the crown. In addition to all that, the five Pandavas (good guys) and the 100 Kauravas (bad guys) are born, then Pandu dies, leaving his five sons orphans. Everyone agrees that the eldest Pandava, Yudhistira should be the first in line for the throne, but his blind uncle King Dhrtarastra has good reason to be resentful for how things worked out, and he won't let us forget it!