At the death of King Richard I of England (Richard the Lion Heart), his brother, John, has seized the throne from their young nephew, Arthur, whose claim to the throne is most likely superior. King Philip of France, upholds Arthur’s claim and sends an ambassador, Chatillion, to demand John give up the throne.
John and his mother, Elinor, denounce Philip and Arthur and plan instead to invade France. As Chatillion leaves, Robert Faulconbridge and his older brother, the Bastard, enter. Robert wants to claim his father’s entire estate, asserting that his brother is illegitimate and sired by the late King Richard I. King John recognizes the Bastard’s resemblance to the late king and offers him a knighthood to leave his brother and go to war in France with them. He accepts, and the king and his armies leave for France.
The English and French armies both arrive before the City of Angiers, and all is made ready for war before the innocent city. Hubert, a citizen of Angiers, appears on the city walls and states that the city will admit neither ruler until it can be ascertained which one is the true king of England. The Bastard suggests that the two parties ally temporarily and conquer the recalcitrant town. As they prepare to do so, Hubert proposes a peaceful settlement: Lewis, the son and heir of King Philip, can marry John’s niece, Blanche of Spain, uniting the two countries. The couple agrees, John grants many of the English territories in France to Philip, and Philip recognizes John’s legitimacy.
The earl of Salisbury brings word of the treaty to Arthur and his mother, Constance. An avid supporter of her son’s right to the throne, Constance rants wildly against Salisbury for bringing the news, against Philip for abandoning Arthur’s cause, and against fortune for favoring King John.
The pope’s legate, Cardinal Pandulph, arrives from Rome to investigate John’s refusal to bow to the pope’s commands. When John refuses to give up his crown and obey other orders, Pandulph excommunicates him, whereupon King Philip, fearing excommunication himself, breaks the recently agreed to treaty. War is resumed, and John takes Arthur prisoner.
After flattering Hubert and hinting of future rewards, King John says he has a secret desire. Hubert offers to fulfill it, and John observes that Arthur is a potential problem to him and speaks the single word, “death.” Hubert responds that Arthur shall die. However, Hubert, preparing to obey and have Arthur’s eyes burned out prior to his murder is so touched by the trusting dependence of the boy that he leaves him unharmed, but plans to fake the death so as not to incur the anger of the king.
In the meantime, Pembroke and Salisbury tell John that many nobles are dismayed that Arthur is kept imprisoned, and the king agrees to free him. Immediately, Hubert arrives and lies to the king, telling him that Arthur is already dead, and the two noblemen leave angrily. The Bastard appears and reports that the country is inflamed over Arthur’s reported murder. Hubert then confesses that Arthur is not in fact dead, and John, relieved, tells him to carry this news to the rebellious lords. However, Arthur, still fearing for his life, attempts to escape from his confinement, jumps from his high window, and dies in the fall. His mangled body is found by Pembroke and Salisbury. Disbelieving Hubert and convinced that John has murdered Arthur, they hasten off to the camp of the French, who, with the pope’s sanction, are invading England.
John, realizing he must make amends with the church, surrenders his crown to Cardinal Pandulph then receives it back again, thus acknowledging the pope as the source of his authority and hoping thereby to ward off the French invasion. However, Cardinal Pandulph is unable to stay Lewis the dauphin, who is claiming the throne in his wife’s name. In the ensuing battle neither side wins a decisive victory. The English nobles who have joined Lewis return to the support of their king. Both sides, weakened, are ready for peace.
Meanwhile, John, feeling ill, has taken refuge in Swinstead Abbey, where he is poisoned by one of the monks and dies, surrounded by his faithful nobles and his son, Henry. Cardinal Pandulph arrives with honorable terms of peace, and Lewis returns to France. The Bastard, swearing loyalty to the new king, John’s son Henry III, says now that internal disputes are over, England will once again be invulnerable to invasion.