I heard there's a story about a ritualistic man from Nashik in Chapter 12. What's the setup for that story and why is it important?

Yes, Chapter 12 introduces a story that it calls "very delightful" and essential for devotees to hear. It sets the stage by talking about a man named Mule, who was a ritualistic and orthodox Agnihotri (a keeper of the sacred fire) from the holy city of Nashik. The chapter explains that he came to Shirdi due to the strength of his past merits, noting that without such merit, no one can stay in Shirdi even for a moment. His visit was a coincidence, as his original intention was different, but this led him to gain the benefit of Shirdi and see his Guru. The story is presented as a prime example illustrating the greatness of the Guru.