The next day, the Yankee reveals his hidden network of nineteenth-century civilization. He posts a new challenge, saying that with 50 assistants on any appointed day he will destroy the entire massed chivalry of the Earth. The knights realize he has the power to do what he claims and fall silent for the next three years. After three years, the country is happy and prosperous, with a flourishing educational system, several newspapers, and widespread equality and freedom. The use of steam and electrical technology is common, and the nobles are given useful employment within the framework of nineteenth- century civilization. The Yankee continues to work on his plans to overthrow the Catholic Church and get a decree issued for universal suffrage after Arthur's death.
The Yankee has married Sandy. Their daughter, Hello Central, comes down with membranous croup, and the Yankee nurses her back to health with the help of Sir Launcelot, who is now president of the stock board. The Yankee and his family go on a cruise for two weeks and then stop off in France. At the end of a month, the Yankee sends for news from Camelot on his attempt to introduce baseball with teams made up entirely of monarchs. Hello Central falls into a relapse, and the Yankee and Sandy spend the next two weeks nursing her back to health again. When she recovers, the Yankee realizes his ship should have returned long ago with news from Britain. He rides to a hill overlooking the English Channel and finds that the usual fleet of merchant ships is nowhere to be seen. He decides to return to England and leaves Sandy and the baby in France.
He arrives and finds the whole country quiet and somber and nearly deserted. It has been placed under the interdict of the Church. The Yankee finds Clarence in a deserted Camelot. Clarence tells him how Sir Mordred and Sir Aglovale, after being bettered in a stock deal by Sir Launcelot, told Arthur of Guenever's affair. This led to war between the king and Launcelot and the death of many great knights of the Round Table. While the king was away fighting, he left Mordred, his nephew, in charge of the kingdom. Mordred took steps to cement his power and had the interdict of the Church placed upon him. The Yankee was included in the interdict. Mordred and Launcelot met in battle and kill each other. The Church has taken power, and Clarence reveals that he has found out the Church has been working against them all along and that the doctors who advised the Yankee to take his daughter on a sea cruise were in the Church's employ. The Church has destroyed the Yankee's nineteenth-century infrastructure, and the Yankee's trained employees have reverted to their previous superstitious states.
Clarence selected a group of 52 faithful boys who grew up under the Yankee's enlightened system and fortified a cave of Merlin's containing an electric plant with electrified fences, Gatling guns, and land mines in preparation for a siege. The Yankee issues a proclamation declaring all the old institutions of the monarchy, aristocracy, and the established Church to be null and void and calling for the people to assemble and elect representatives to govern them in a new republic. Then, he and Clarence hasten to Merlin's cave. The Yankee sends word to all his factories and centers of civilization to evacuate all personnel, as he plans to blow them up with secret mines connected to the cave with wires.
Nothing happens for a week, and the Yankee spends his time turning his journal into the narrative of the book. The nobles turn out to wage war on the Yankee and his followers for the Church, and it soon becomes apparent that the common people and even the former slaves have reverted to their previous subjugated states and joined the cause. All England turns out to destroy the Yankee and his dream of the republic. The boys approach the Yankee one day and tell him they cannot fight their own people, but the Yankee has prepared an answer. He tells them that the 30,000 knights will advance first, and when they hit the mines and begin being blown apart, the commoners will desert them, so that the boys will only have to fight the hated nobility. The boys are reassured and return to their posts.
The day of the battle arrives, and the knights lead the charge, just as the Yankee foretold. The first wave reaches the line of mines and explodes. The Yankee pushes a button and destroys his network of civilization-factories. The smoke clears, and the massed army is nowhere in sight. That night, the knights gather in the ditch created by the explosion in preparation for a sneak attack. The Yankee sneaks out and keeps a close watch on their progress and kills eleven thousand of them with the electrified fences. He catches the remainder of the knights between the ditch and the fences and gives the signal for the ditch to be filled with water. They open fire on the knights with Gatling guns, and the knights retreat back into the ditch, where they drown.
Twain narrates another important incident with an excerpt from Le Morte D'Arthur, this time the actual death of Arthur. Twain chooses to do this perhaps because the Yankee does not witness the event firsthand, and he feels he cannot improve (or is unwilling to try to do so) on Malory's third-person telling of it. The Yankee makes sweeping reforms during the three years after the tournament by exploiting existing prejudices--in putting the nobles to work by creating an aura of elitism and exclusivity around certain positions, for instance. They retain parts of their old lives, as they still wear armor, and continue in their old vices, as they steal from the company.
The Yankee's opinion of the nobles softens a great deal when he has them working for him. Violence is still common in the Yankee's system, as his wandering knight missionaries dispatch anyone who doesn't buy his products. The Yankee is not above suppressing free speech and has Sir Dinadan hanged for publishing a book containing the anecdote he so detests (a rather discordant note in Twain's humor as he again gives free reign to one of his personal pet peeves). The Yankee wants to give all men a vote, but he considers limiting women's suffrage to middle-aged women on the basis of a test of their knowledge compared to their sons; it is unclear whether this is a political compromise or if it reflects the Yankee's own bias. The Yankee wants to be the first president of his new republic, which forces him to admit that he is just as much a product of human nature as anyone else.
Clarence now speaks perfect nineteenth-century English and shares most of the Yankee's views. He differs from the Yankee on only one point, advocating the continuance of a hereditary royal family, but he takes very little seriously and it is unclear how much of his argument expresses his true opinion and how much is purely joking. He almost convinces the Yankee to establish a royal family of cats; this seems to expose the Yankee's somewhat impractical affinity for wild schemes again. The Yankee does not truly love Sandy when he marries her (he is still in love with Puss Flanagan, presumably), but he grows to love her very much. The Yankee shows himself to be a tender father, and he stops thinking of himself as the most important person in the world and starts thinking of his child that way.
The first hint of trouble in this section is the Yankee's cryptic comment about the last time he sees Launcelot. The Yankee feels the darkness of Camelot upon his return from France is an omen that the Church has won once and for all and will blot out all his efforts. The Church is portrayed as actively anti-technology and anti-democratic, but this is not entirely without historical precedent. Also, the Yankee is staunchly anti-Catholic, so it is reasonable that the Church would take action to defend itself. The eerie sequence with all the silent electrocutions in the dark could be interpreted in terms of technology's dehumanizing effects, especially the scene where Clarence and the Yankee find the dead knight standing with his hands on the wire and cannot identify him.
The knight who dies when he touches his dead friend could be taken to prefigure the downfall of the Yankee's followers, who fall ill from the corpses of the knight, many of whom must have once been the Yankee's friends. The scene where the Yankee lights up the night with his electric lamps is emblematic of his technological revolution; the indiscriminate massacre that follows shows how completely his dreams of bloodless reform have soured.