Outside the town of Angers, King Philip of France walks with the Dauphin Louis, Constance, Arthur, and the Duke of Austria. Arthur and Constance thank Austria for joining the forces gathered against the English. Philip urges his men to ready themselves for an attack on Angers if the town doesn't swear allegiance to Arthur. Chatillon returns from his journey to England and urges Philip to turn the troops to a mightier battle, against the gathered English forces who are right behind him. Led by King John, who is accompanied by Eleanor and Lady Blanche of Spain, these forces are enormous and even include the bastard son of Richard the Lionhearted.
John enters with Eleanor, Blanche, the Bastard, and Pembroke. John offers peace to the French, but only if they accept his royal lineage. Philip too wishes John peace, but only if he takes his forces back to England without a fight and gives Arthur the crown of England. John asks Philip what has made him the judge of the situation, and Philip replies that heaven above has made him guardian of Arthur and a champion of his rights.
Eleanor interrupts, calling Arthur a bastard. Constant replies angrily, accusing Eleanor of infidelity to her husband, Henry II. Austria and the Bastard exchange insults, until Philip interrupts both parties. He lists Arthur's claims to John, which include full possession of English lands in Ireland and France. John says he would rather fight than lay down the throne. Eleanor calls to Arthur, trying to lure him away from the French, but Constance mocks Arthur to keep him in line. The sweet-tempered Arthur weeps, wishing he were not in the middle of the argument. Constance and Eleanor exchange harsh words again; Constance insists that the law says Arthur is the rightful king and accuses Eleanor of having committed adultery in giving birth to John, whom she again calls a bastard.
Philip silences them again and suggests that they ask the citizens of Angers whether they will accept John or Arthur's claim to the throne. John asks the citizens to open their gates, threatening destruction otherwise. Philip, speaking for Arthur, tells the citizens of Arthur's claim to the throne and asks that they accept him instead. The citizens acknowledge that they are England's subjects, but they will not open the gates until John or Arthur is able to prove they are the king. John offers his crown and his troops as proof of his leadership; Philip says as many men stand against him to contradict that claim. The citizens repeat their decision, so John and Philip urge their armies on and exit to battle.
A French and an English herald appear at Angers's gates, announcing the bloody outcome of the struggles and ask that the gates of the city be opened for their respective leaders. However, the citizens of Angers have seen that the armies are equally matched, neither able to prove itself superior. Therefore they will keep their gates closed until one side proves greater. Each king, with his train, reenters the scene, threatening to bring about the deaths of more soldiers in battle. They appeal to the citizens, who again refuse to open their doors.
The Bastard comments that the citizens of Angers flout both Philip and John, and they stand on their walls, watching the battle below like a play performed for them. He urges the two armies to merge temporarily and punish Angers for its audacity. Once they destroy Angers, they can break their alliance and continue to fight one another. John likes the suggestion, and Philip agrees. The citizens call to the kings and urge them not to follow this path of destruction, but instead to listen to another idea.
A citizen points out Blanche, the daughter of the King of Spain, a niece of the English royal family. Then he points out young Louis, who would make such a good match for her. Such an ambitious marriage would join several kingdoms in bonds of peace, and it would open the gates of Angers so much more easily than war. The Bastard comments to himself that the citizen's idea surprises him; his success at urging each side on to war has been trumped by the words of the citizen.
Eleanor advises John to agree to the match, for such a tie with France would assure John's hold on the crown. John tells the French that if Louis likes Blanche, he will offer a dowry of several English-held French territories. Philip asks Louis how he feels about Blanche, and Louis replies that he is transfixed by her. The Bastard comments to himself on Louis's swift enrapturement, as Blanche replies that she will do as John commands, but she also looks favorably on Louis. Both kings agree to the match, and Louis and Blanche join hands and kiss.
Philip asks the citizens of Angers to open their gates, then looks around for Constance. Louis thinks she must be in her tent, upset about the turn of events. John says they'll fix things by giving Arthur a dukedom. All depart except the Bastard, who comments on the madness of kings. In order to stop Arthur's claim to the throne, he gave away a part of his lands to Louis. France came to the battlefield full of conscientious efforts to help Arthur, but left with another result entirely. The desire for gain and commodity converted an honorable war into a vile and weak peace. But this commodity has not yet wooed him, the Bastard declares, and while he's still poor he will rail against the rich. But because even kings are willing to break their allegiances for the benefit of commodity, then he too will worship the gods of gain.
At the French camp, Constance and Arthur receive news from Salisbury. Constance can't believe that Philip has broken his ties to her. When Blanche and Louis are married, Louis will gain the territories Arthur should have held. She curses Salisbury, while Arthur tries to soothe her. She tells Arthur she wishes he had been malformed at birth, for then she would not love him or think that he deserves a crown. But instead Arthur is blessed by Nature, if not by Fortune. Fortune has been turned by John, just as France was. Constance's grief is so great that nothing can support it but the Earth, where she sits.
While Philip and John try to assert their authority by convincing the citizens of Angers to open their gates, Constance and Eleanor verbally attack each other, accusing the other of having carried out several of the greatest crimes of a married woman, including adultery and giving birth to a bastard child. While the two women seem to be arguing alongside the larger battle between Philip and John, it's not clear how much of the entire operation may have been urged on solely by them.
The armies fight but neither can prevail, so the malicious influence of the Bastard convinces the kings to join forces to destroy Angers, merely to prove that the kings won't endure disrespect. Such a temporary truce is in opposition to the original intent of attracting Angers, an assault meant to prove the true king of England through Angers's acceptance of John or Arthur as king. Destroying Angers makes such a selection impossible, for there will be no citizens left alive to choose. Yet the Bastard's clever rhetoric is derailed by the citizens, who suggest another surprising alternative.
In agreeing to the marriage of Louis and Blanche, each army leaves with a different result than they had intended. Philip planned to help his ally Arthur get to the throne of England; instead his son marries a relative of John, creating different ties of allegiance. But Philip only wants allegiance with England and does not care about his broken ties to Arthur. John wanted to defeat Arthur and affirm his ties to the throne; instead he strengthens his position by marrying his relative to Louis, but in the process gives away some of the very lands he intended to rule. Both leave with richer ties of allegiance between the two countries, but poorer in other ways. Philip has shown himself to be fickle and untrustworthy in allegiances, and John has given away some of his territories in his desire to keep Arthur out of the rest of them.
The Bastard is startled by all the reversed intentions. Learning fast the ways of the nobles, he sees that greed plays a huge role in John and Philip's decisions. Denouncing the nobles for their opportunistic behavior while he is still poor, he admits that he fully intends to mimic them and gain riches. He too will be out only for himself, seeing such behavior in the models presented before him by Philip and John.