What is the plot of The Prophet of Zongo Street?

"The Prophet of Zongo Street" is told from the perspective of a nine-year-old narrator. The narrator lives in the crowded city of Kumasi, found in the West African country of Ghana. Here, the narrator recalls Kumi: a local post office worker whose family abandoned him. Kumi is shy and book-smart—a recluse but well-liked. He often invites the boys in his neighborhood to his house to lecture them about philosophers, happiness, and religion.
The narrator is the only boy who genuinely seems interested in Kumi and considers him a friend. One day, Kumi gives him a book called Manifestations and tells the narrator that he cannot see him anymore—he needs to study in isolation. The book seems scandalous to the narrator; it says Christianity and Islam were never indigenous to Ghana but instead brought by invaders and colonizers.
Three weeks later, Kumi emerges from his home, bearded and emaciated. He begins preaching in the street zealously—day and night, rain and shine. Kumi says the Muslim people of the neighborhood have been practicing a long tradition of lies—that, centuries ago, Arab invaders brought their people a false, white prophet. He tries to tell them that their God is as black as them and continuously preaches a new religion. People gather around at first, but they quickly dismiss Kumi as a nut. The narrator tries to talk to Kumi, but the man does not seem to recognize him.
Kumi continues to preach without food or rest, even though no one listens. One day he stops. Three days later, some town people break into Kumi's house and find him dead on his bed. It seems the only person who learned something from Kumi's knowledge is the narrator, who continues to read passages from Manifestations in secret.