Despite early rumors that Hotspur has defeated the King's forces, the true report of the defeat of the rebels and the death of Hotspur is finally brought to the Earl of Northumberland, leader of the insurgents. Northumberland is also informed that the King's forces are leading an army against him. Enraged, he joins forces with the Archbishop of York.
In London Falstaff is finding it difficult to bid farewell to his associates at the Boar's Head Tavern and to start north with the King's forces, enlisting soldiers en-route. This "hasty employment in the King's affairs" saves him from being arrested for debt at the suit of Mistress Quickly, and the clever rascal concludes the whole matter by borrowing more money for riot and jest with Prince Hal and their other companions.
In the North, Northumberland's wife and Hotspur's widow prevail upon the cold-blooded nobleman to desert the Archbishop of York and take refuge in Scotland. The King, in Westminster Palace, is enfeebled by anxieties and ill health as he discusses the rebellion with his counselors, Warwick and Surry. As the monarch beholds the truth of Richard II's prophecy regarding Northumberland, he realizes that "uneasy lies the head that wears a crown" and wishes the wars were out of the way so that he could make the long-deferred pilgrimage to Jerusalem.
In Yorkshire, the insurgents are chilled by the news of Northumberland's defection. They are prevailed upon to present a list of their grievances to John of Lancaster (Hal's brother and leader of the king's forces) who swears princely redress. Upon this royal word the rebel armies are dispersed, but immediately the prince orders the rebel noblemen executed and their followers slaughtered. The report of this act reaches the king in Westminster together with the news that Northumberland has also been defeated, but the king is too ill to hear even good tidings, putting his crown upon a pillow and falling into a stuporous slumber. Hal, summoned to the palace, thinks the king is dead an sorrowfully removes from the room the golden circlet of his father's cares. Awakening alone and misunderstanding his son's action, the king accuses him of desiring his death, but the genuine grief of the young prince is apparent, and the two are reconciled. The dying monarch advises his son to let the rebellion at home slumber.
Upon the death of his father, Prince Hal becomes the ruler as Henry V. The news of these events speeds to Gloucestershire, and Falstaff hurries to London to reap the benefits of his long companionship with the prince. He finds, however, that the young king is not the old riotous prince.