The train arrives in Montana in "the village of Fish," a mysterious small town occupied by twelve men (2.1). Every once in a while, the transcontinental train on which Percy and John are now riding stops in this village of Fish, and the men who live there congregate to see the rare event. The narrator makes the point that these men of Fish are without religion, so they impart no spiritual significance to this strange, ritual occurrence.
Percy and John disembark and, in front of the twelve men of Fish, get into an old buggy and drive away from the depot.
After about half an hour of buggy driving in the dark of night, the black driver pulls the buggy over. They are approached by a huge, magnificent, gleaming automobile, greater than anything John has ever seen. Two black men get out of the automobile, "dressed in glittering livery such as one sees in pictures of royal processions in London" (2.5).
As the men transfer all their luggage, Percy explains to John that they couldn't get into the car right at the depot. It would never do for the men of Fish to realize that there was a family living nearby with that kind of wealth. While John gushes over the car, Percy writes it off as a piece of old junk that they use as a station wagon.
The boys travel for over an hour, heading towards a break between two mountains in the distance. Finally, they come to a stop at a small cliff. They meet up with several more black men who, with a series of cables and ropes, lift the car up to the plateau that was above them.
Percy tells John that this is where the United States ends. They are in the middle of the Montana Rockies, but inside five square miles of the county that has never been surveyed. It turns out that Percy's family has been protecting these five square miles from discovery for generations.
Now there's only one thing his father is afraid of, says Percy: airplanes.
The family shoot down anyone who flies overhead and then keep the aviators prisoner. It's a great worry for them, however, that someone might get away some day.
John begins to wonder what "terrible and golden mystery" lies hidden in these five square miles that must so urgently be protected (2.26).
Finally, they arrive at Percy's house – a magnificent château on the border of a lake and a forest of pine. It's a giant edifice with "a thousand yellow windows" and "many towers", flooded with golden light, the sound of violins, and the fragrance of flowers" (2.28).
As they ascend the great steps, the front door opens and John is introduced to Percy's mother.
Inside John is dazzled by the diamond-covered walls; the opulence of the interior is described in excessive detail.
John is so overwhelmed that he falls asleep at dinner with Percy's family. He wakes up in bed, where the servants have placed him, to find Percy standing over him. He apologizes for ever having doubted that Percy indeed had a diamond as big as the Ritz.
Percy explains that the diamond is the mountain on which their house rests. But before he can respond, John falls asleep again.