Mateo Melgarejo is a notary public and scribe for the illiterate people of Santo Domingo, a neighborhood north of Mexico City's Zócalo. A squatter friend asks for his help in negotiating with the land census bureau to regularize a land title. After a great deal of frustration with the government bureaucracy, he writes a letter to the cabinet minister, earning an audience with him. The minister hires Melgarejo to reform the bureau, and the appointee proceeds to lecture the officials on their duties in a democratic society. At the end, he gives up the post, returning to Santo Domingo to help its poor residents.
