Seventeen-year-old novice Gerard Francis of Utah meets a pilgrim during his Lenten fast in the Utah desert. He holds his vigil sometime in the 20th century. As he sits, an old pilgrim approaches, heading toward Leibowitz Abbey. Francis watches as the traveler overturns a large rock, kills the snake beneath it, then takes shade under the ledge he has created. As he breaks bread, the man sings a prayer to Adonoi Elohim—a name that Francis doesn’t know.

Most people in the desert have deformities, and Francis notices that the pilgrim doesn’t appear malformed in any way. Francis clears his throat, and the man sees him, then asks if they are near Leibowitz Abbey. When the man offers him bread and cheese, Francis splashes him with a vial of holy water, worried that the pilgrim is a demon that will tempt him to eat during his fasting vigil.

The pilgrim notices a gap in the small shelter Francis built from stones. He finds a stone that Francis can use to finish an arch in his shelter, tells him where it is, and leaves. When Francis investigates the stone, he sees that the pilgrim has written two symbols on it: letters from the ancient Hebrew alphabet.