London is an ancient city; at the time of Twain's story, it is fifteen hundred years old and filled with a hundred thousand people — or maybe twice that number. The streets are narrow, crooked, and dirty, and in the part of town where the Cantys live, the streets are even more narrow, even more crooked, and are dirtier than most streets. The Cantys' house in Offal Court, out of Pudding Lane, is filled with the poorest of London's poor. The six members of the Canty family live in one room on the third floor of an old, decaying house. There is a bed for the parents, tucked in a corner, but "Tom, his grandmother, and his two sisters, Bet and Nan, were not restricted — they had all the floor to themselves, and might sleep where they choose." As a result, they sleep on some bundles of dirty hay that can be kicked back into a corner the following morning.
Tom Canty's father and grandmother are thieves and beggars — and are also often drunk and violent. They make the children beg, which the children do, but they will not steal. Life is hard; Pudding Lane and Offal Court are both drunken, brawling, riotous places, but young Tom Canty is largely unaware of how really bad his life is. He goes out in the morning and begs; if he returns empty-handed, he is roundly cursed, then beaten. Thus he begs enough to save himself from being beaten, but he spends most of his time listening to Father Andrew's old tales and legends. Father Andrew teaches Tom and his sisters "the right ways," and, in addition, he teaches Tom how to read and write and also some Latin. Father Andrew's tales fill Tom's mind and take away some of the pain of the beatings and hunger which the boy must endure, and they also feed Tom's desire to be clean — in body, mind, and spirit. For example, he sometimes pretends to be one of the princes in Father Andrew's tales, and he has come to gain a measure of stature among both the children and the adults who bring him their problems; they are quite often amazed by the wisdom with which he solves their troubles. Meanwhile, however, Tom harbors a deep, secret desire: to see a real prince.
One January day, Tom wanders through the city, aimlessly ambling farther and farther from home than ever before. Eventually, he finds himself outside the walls of London and on the Strand, where there is a scattering of the palaces of the rich. Aghast at what he sees, he walks into Charing Village, past the cardinal's palace and goes on toward Westminster, a vast building with colossal granite lions and other signs and symbols of English royalty. When he comes to the fence surrounding Westminster, he catches a glimpse of the sturdy, tanned, beautifully-dressed Prince of Wales.
The noise of a soldier pulling Tom from the fence attracts the attention of the prince, who invites Tom into the royal grounds. The young prince takes Tom into a richly appointed apartment, treats him wonderfully, and feeds him all sorts of delicious treats. He asks many questions about Tom's life and is upset by what he hears, but he is fascinated by the stories of race and other sports played in Offal Court that Tom tells him about. The prince is as curious about Tom's life as Tom is by what he has seen of the prince's life. Impulsively, the two boys decide to exchange clothing and they discover, afterward, how very much they look alike.
Discovering a bruise on Tom's hand, the prince dashes out to reprimand the guard, but Edward forgets that he is wearing Tom's rags and he is treated like an upstart and a beggar. Furthermore, he is immediately hustled off to London in the midst of a hooting and shouting crowd.