What is the central narrative hook introduced in Chapter 20 involving Das Ganu's scholarly work?

The central narrative hook presented in Chapter 20 revolves around Das Ganu's spiritual and intellectual impasse. He was attempting to write a simple commentary on the profound Ishavasya Upanishad but became stuck, unable to comprehend its inner meaning. He sought guidance from his Satguru, Sai Baba. The compelling part of the story is Baba's mysterious instruction. Instead of providing a direct explanation, Baba prophesied that the doubt would be resolved by a humble maidservant at Kaka's house, setting the stage for a lesson on how divine wisdom can be imparted through the most unexpected channels.