This text has two narrators: one is a middle-aged Peruvian man who has traveled to Italy in order to "forget Peru and the Peruvians for a while," and the other is, apparently, a Machiguengan storyteller. Although it is never stated explicitly, it is implied (and the first narrator comes to believe) that the storyteller is a man named Saul Zuratas, an old friend from the first narrator's childhood and college years.

When the book opens, the first narrator has seen a photograph of a storyteller in the Amazon, and he believes—though he is not sure—that the man in the photo is Saul. As a child, Saul earns the nickname Mascarita due to a large, dark purplish birthmark that covers one half of his face. Despite the terrible treatment Saul receives from others, he is always kind and calm in return. In college, Saul begins to question the work of scholars who are studying the Machiguenga, a native population in Peru.

Chapters narrated by the storyteller cover a range of topics from Machiguengan cosmogony to folktales to cultural practices. It is a major part of their culture that they keep moving, keep walking, maintaining a nomadic kind of lifestyle, or else, they believe, the Sun will fail.

The first narrator presents the concerns that many have about scholars attempting to study the Machiguenga—that they are like "a tentacle of American imperialism which, under cover of doing scientific research, has been engaged in gathering intelligence and has taken the first steps toward neocolonialist penetration of the cultures of the Amazonian Indians." Saul wants to preserve tribes just as they are by leaving them alone. The narrator describes the Christian missionaries who attempt to infiltrate the Machiguenga and learn their language so that they can translate the Bible and provide the natives with the book in their own tongue. He continues to have a relationship with Saul, and they argue over whether it is best to try to educate the Machiguenga about the Peruvian culture and economy so that they cannot be so easily exploited or to leave them alone (despite their exploitation and victimization by mainstream cultures).

Eventually, the narrator learns that Saul and his father have moved to Israel (they are Jewish). However, many years later, he discovers that this is not true, that Saul's father died in Peru and was buried there, and he begins to formulate a theory that Saul abandoned Peru, Judaism, the university, and his own identity, in order to live with the Machiguenga. A late chapter narrated by the storyteller, in which he references his own purplish facial birthmark, seems to confirm this, but it is never explicit. Through the text, the first narrator has spoken to others who have had or himself had difficulty getting the Machiguenga to discuss their storytellers. Strangely, it seems to be an incredibly taboo subject. Once the narrator begins to piece Saul's history together, he realizes that Saul must have asked the Machiguenga to keep the secret of his identity. The book ends with the narrator's near-certainty that the man he sees in the photograph in Florence is truly Saul, having been embraced by the Machiguenga and made a part of their community.