The pilgrim's inner journey begins when he is struck upon hearing the words of Paul (in I Thessalonians 5:17) to "pray without ceasing." He visits churches and monasteries to try and understand how to pray without ceasing. His travels lead him to a starets (a spiritual father) who teaches him the Jesus Prayer—"Lord Jesus Christ have mercy on me"—and gives him practical advice on how to recite the prayer uninterruptedly, as a type of mantra.

The book details the gradual spiritual development and struggles of the narrator, and the effect the narrator's spirituality has on those around him.