Gloucester and his wife, Eleanor, the Duchess, talk. She asks why he is so gloomy. Does he dream of Henry's throne, she asks. Gloucester tells her to banish such ambitious thoughts, explaining his bad mood comes from his unsettling dreams. He saw his staff, the badge of his office, broken in two, and impaled on the end of each half were the heads of Somerset and Suffolk. The Duchess, too, has had dreams; she saw herself in Westminster Abbey, about to be crowned as queen, with Henry and Margaret at her feet. Gloucester, astonished, chides her, reminding her that she is the second woman in the realm, behind only Margaret. He demands that she must not hatch any treachery that will bring harm to him.
A messenger enters, asking Gloucester to join the king at Saint Albans, where the lords are hunting. He leaves. The Duchess considers how, if she were a man, she would much more easily remove the stumbling blocks between her and the throne. But, being a woman, she must play a role. She calls in Sir John Hume and asks him if he has spoken with the witch and conjurer to ask them to advise her about the future. Hume says they have promised to raise a spirit to answer all the questions. She gives him money to complete the deal and she leaves. Hume remains, pondering that the Duchess has given him gold to hire a witch, while Beaufort and Suffolk have also given him gold to help undermine the Duchess and urge her to dabble in the occult. He's playing both sides, he realizes, and he will bring about the fall of Gloucester through the ruin of the Duchess.
Several petitioners, including Peter, enter the palace, searching for Gloucester, whom they believe to be a good man who can help them. Suffolk and Margaret enter; one petitioner believes Suffolk is Gloucester, but another insists it is Suffolk. Suffolk asks what the petitioners want. One petitioner offers up his complaints. Realizing they are addressed to Gloucester, Margaret eagerly reads the papers. The second petitioner's complaint is against Suffolk, but nothing interests Suffolk until he hears Peter's complaint against his master, Thomas Horner, who Peter claims has said the Duke of York is the rightful heir to the crown. Suffolk pays attention to Peter and sends him off to make his complaint formally. Meanwhile, Margaret rips up the other petitioner's papers.
Margaret asks Suffolk if court details are normally dealt with by Gloucester instead of Henry; as the queen, must she be subject to the rulings of a mere duke? She tells Suffolk that she thought Henry would resemble Suffolk in bravery and seductiveness, but Henry is weak and more concerned with prayer and his religious life. Suffolk tells her to be patient; just as he was the cause of her becoming queen, so he will make things work out for her in England. The two discuss all their enemies, from Beaufort and Gloucester to Somerset, Buckingham, and York, and finally Salisbury and Warwick. Plus, says Margaret, there is the Duchess to worry about; Margaret can't stand the Duchess's haughty manner, behaving as if she is the highest lady in the land. Suffolk says he has set a trap for her already. And while they don't like Beaufort, they must side with him until Gloucester has come to disgrace. And as for York, Peter's complaint may help bring him down. So little by little, they will weed out their enemies.
Henry enters with York and Somerset, followed by Gloucester, the Duchess, Buckingham, Salisbury and Warwick, and Beaufort. York and Somerset disagree over who should become regent of France, while Henry says he doesn't care who gets the job. The other lords join in, suggesting their preferred candidate. Gloucester says the king should decide, but Margaret demands to know Gloucester's role now that Henry is of age. He reminds her that he is the protector but willingly would resign if she wishes. Suffolk, Beaufort, Buckingham, and Margaret accuse Gloucester of making a mess of the kingdom. Gloucester, insulted, leaves. Then, Margaret drops her fan and asks the Duchess to pick it up, punching her in the ear when she leans down. The Duchess is enraged, promising revenge, and storms out. Gloucester returns, calmed, and urges the king to make York the regent of France. York says he would be a bad candidate for regent, for Somerset's delay in providing him with men and equipment would delay him until France fell to the king of France.
Horner and Peter enter. Suffolk explains that Peter accuses Horner of saying York was the rightful heir to the throne. Horner denies such accusations, but Peter repeats them. York asks for justice in treatment of these villains. Horner suggests Peter's accusations come from anger at Horner correcting Peter's work. Gloucester recommends that Somerset become the regent of France, as the case brings suspicions against York. And he recommends that Horner and Peter settle their differences in armed single combat. Henry agrees and Horner is satisfied, but Peter is hysterical; he doesn't know how to fight and worries he will die. The two men are taken to prison to await their battle.