Richard Plantagenet, the duke of York, enters the throne room with his sons and followers, wondering where King Henry has fled to after their recent battles. Warwick urges York to take the throne. As York sits, Henry enters with his supporters, who want to fight York right there. Henry urges calm and asks York to descend from the throne. York announces his claim to the throne, while Henry defends his hereditary possession of the Crown. However, suspecting that his claim may indeed be spurious, Henry asks York to let him rule while he lives, and he will pass the throne on to the house of York on his death. York agrees and departs, but Henry’s supporters are astonished that he would disinherit his son. Margaret, Henry’s queen, arrives and accuses him of being an unnatural father. She also chides him for thinking that York will let him rule.

Back in the town of York, York’s sons Edward and Richard, along his follower Montague, urge him to take the throne immediately rather than wait for Henry’s death. York insists he has sworn an oath to let Henry rule, but Richard convinces him that the oath wasn’t binding.

The scene shifts to Richard’s other son, Rutland, as he is captured and killed on the way home by Clifford, who wants to avenge his father’s death at York’s hand. 

Meanwhile, Margaret has taken command of the king’s forces and led them to York, where they are now leading a victorious battle against the duke’s troops. York is captured by Margaret and Clifford. The queen offers him a handkerchief dipped in Rutland’s blood and challenges him to wipe his tears with it. York rails against her, calling her unnatural, and Clifford and Margaret stab him to death.

Edward and Richard wonder about the fate of their father, when they see a vision of three suns on the horizon. Edward believes it is a sign that the York brothers must act as one. Richard also thinks the sign symbolic, but he’s less clear about his interpretation. A messenger arrives with news of York’s death, and the brothers are devastated. Warwick and Montague prepare to spar again with Margaret’s forces, this time aided by the troops recently brought from France by York’s other son, George.

Margaret and Clifford, with their followers, meet Henry at the town of York. Clifford urges Henry to undo his son’s disinheritance, but Henry isn’t convinced that sons appreciate what their fathers leave them. After all, he doesn’t enjoy the legacy bequeathed to him by his father, Henry V. Just then, Edward and his men burst in and demand the throne. The nobles from each side insult each other, and Henry tries to speak, but none will listen to him. Edward blames Margaret’s pride for the civil war, and he declares that they will have to move their dispute to the field of battle, since she won’t let Henry speak.

Richard hunts Clifford on the battlefield to avenge the deaths of his father and brother. The tides of the battle ebb and flow as Henry watches from afar. He sees two soldiers drag dead bodies away from the scene of the fighting, trying to find valuables to steal. As the soldiers remove the armor from the bodies, one discovers he has accidentally killed his own father, and the other, his son. Henry mourns that the kingdom has descended to this level of unnatural butchery. Henry’s son, Prince Edward, urges him to flee.

Clifford is wounded and dies. Edward sees he has won the battle, though Henry is nowhere to be found. His company heads to London to crown Edward and to give new titles to Richard and George. Meanwhile, as Henry flees to Scotland, he is arrested in a forest by two gamekeepers who support Edward.

Margaret goes to France to ask King Louis for aid, and Edward sends Warwick to France to ask for the hand of the French king’s sister-in-law.

In London, a dispossessed widow named Lady Grey petitions Edward to get her land back. He takes a liking to her and asks her to marry him. But his brothers are annoyed to hear Edward announce his imminent marriage. They are also irritated by Edward’s plan to arrange a desirable marriage for Lady Grey’s brother, since he should be making such arrangements for his own brothers.

Richard, alone, considers his future. Many people stand before him in the line of succession, so it seems unlikely he will ever become king. And yet he believes his physical abnormalities, including a humped back and withered arm, make him undesirable and will prevent him from enjoying a life of sensual pleasure. Therefore, nothing remains but for him to scheme for the Crown. He decides he will play the role of the good brother and subject while he plots to eliminate everyone standing between him and the throne.

Margaret and Warwick arrive at the French court at the same time. King Louis decides to give the hand of his sister-in-law, Lady Bonnë, to Edward, thus denying Margaret the aid she asks for. But just then a messenger arrives with news of Edward’s marriage. Insulted to have been sent on a futile errand, Warwick changes sides, pledging his allegiance to Henry. Louis gives Margaret troops to fight with Edward.

In England, Edward and his brothers and lords discuss his marriage. They receive news that Warwick and Margaret have joined forces. George is so upset by Edward’s new marriage that he leaves with Somerset to join Warwick. In preparations for the coming battle, Edward is captured. Seeing George on the enemy’s side, Edward gives up the throne and consents to be imprisoned at Warwick’s brother’s estate. Yet Richard and Hastings soon spring Edward from his gilded prison.

Warwick, George, and their supporters find Henry in the Tower and free him. Henry says he wants to be king in name only, and he appoints Warwick and George as joint Protectors of the Realm. They receive word that Edward has escaped to Brittany, from which he soon returns with reinforcements. Arriving back at the town of York, Edward thinks he wants only to be the duke of York, but his followers urge him to seek the throne.

Henry’s followers go to gather troops to take on Edward’s army. Edward and Richard capture Henry and send him to the Tower before they march to meet Warwick’s army. As their two armies meet, Edward asks Warwick if he will again swear allegiance to him, but Warwick refuses. Warwick’s supporters then arrive, including George. But before the battle ensues, Richard convinces George to break with Warwick and recommit to his brother’s cause.

Warwick is wounded in battle and dies. Warwick’s surviving supporters, Somerset and Oxford, go to join Margaret’s army. Margaret urges her forces on, and they meet Edward’s army. When Edward wins this battle, he sends Somerset and Oxford away, kills Prince Edward, and imprisons a mourning Margaret. Richard then sneaks off to the Tower, where Henry awaits.

Henry prophesies that thousands will suffer because of Richard’s future deeds, for Richard was born under the most inauspicious and evil signs. Richard kills Henry and declares himself separated from the ties of family and brotherhood. Since he was punished by the heavens with such unfortunate physical attributes, he will henceforth fight for himself alone. And with Henry and his son out of the way, Richard’s next goal is to eliminate George and Edward.

Edward’s son has been born, and George and Richard kiss the child. Edward calls for festivities to celebrate his attainment of the throne. Peace, he believes, has finally settled over England.