What story is introduced at the end of Chapter 12, and what is its stated purpose?

Towards its conclusion, Chapter 12 begins to set the stage for a "very delightful story" meant to illustrate the greatness of the Guru. The story features an orthodox, ritualistic Agnihotri (a keeper of the sacred fire) from the holy city of Nashik, whose surname was 'Mule'. According to the text, he came to Shirdi due to the strength of his past merits, as the chapter claims that no one can stay in Shirdi even for a moment without such merit. It is hinted that his original intention for the visit was different from the eventual outcome, which was that he "gained the benefit of Shirdi and his own Guru came into his sight."