King Richard conducts a hearing wherein Bullingbrook, the Duke of Herford, accuses Thomas Mowbray, the Duke of Norfolk, of treason. Mowbray denies the accusation but not as vehemently as he would have liked, attributing his restraint to the king’s kinship to Bullingbrook (they are cousins). Bulllingbrook dismisses Mowbray’s stated sensitivity as cowardice, however, and officially challenges him to a knight’s duel, accusing him of unlawfully profiting from the state coffers, of plotting the death of the Duke of Gloucester, and of being the source of every instance of treason in the past eighteen years. When Richard assures Mowbray that the king’s kinship to Bullingbrook won’t predispose him in Bullingbrook’s favor, Mowbray accepts Bullingbrook’s challenge. He explains that his profits were justly earned, and that whatever wrong he may have committed is limited to his plot to kill John of Gaunt for which he had confessed and had asked for forgiveness. Despite the intensity of the opposing passions, Richard decides that the two should forgive and forget. They refuse to back down, however, leaving Richard with no choice but to grant them their duel.
The Duchess of Gloucester exhorts John of Gaunt to actively seek redress of her husband’s and of John of Gaunt’s brother’s murder, but to no avail. Attributing his brother’s death to the will of heaven, Gaunt says that the offender will eventually get his just desserts as heaven will see fit. When the Duchess questions Gaunt then to whom should she appeal for justice if not to Gaunt, Gaunt replies to heaven. Crestfallen, the Duchess wishes her nephew, Bullingbrook, the best, expressing her hope that he will slay Mowbray or failing that that Mowbray will be thrown from his horse and break his neck. She leaves Gaunt, telling him to dissuade Edmund York, her brother-in-law, from visiting Plashy as the house will be too grief-stricken to receive visitors.
We are in Coventry on Saint Lambert’s day, the place and time where and when Bullingbrook and Mowbray are scheduled to engage each other in mortal combat. They are both arrayed in knight’s armor. By and by, they are both ordered to declare his respective identity and his respective cause. Both do so. Then Bullingbrook requests that he and Mowbray be permitted to seek the king’s blessings and to say their final farewells to their friends and loved ones as one or the other will certainly die. The request is granted. Bullingbrook receives Richard’s blessing, but is told that if he were to be slayed that vengeance will not be sought on his behalf just because they are cousins. Bullingbrook replies that the king owes him no such loyalty and then says goodbye to his cousin Aumerle and to his father who wishes him a triumphant victory. Mowbray himself receives the King’s blessing and with that the adversaries are brought to face one another. The signal is given for the combat to begin when the King suddenly suspends the proceedings. He orders the combatants to drop their weapons and to approach and hear what the King and his advisers have decided upon. Bullingbrook and Mowbray approach, and they are told that for the sake of preserving the kingdom's peace the King and his advisers have decided to exile both Bullingbrook and Mowbray: Bullingbrook for ten years, Mowbray for life. Mowbray objects but to no avail. On account of Gaunt’s grief for his son, Richard abridges Bullingbrook’s exile to six years, but Gaunt is inconsolable. The decisions will stand, however, and Richard has Bullingbrook and Mowbray vow that the two will never exchange communication while in exile and conspire to plot against the King.
Bullingbrook has just left to serve his six year exile, and Richard asks Aumerle what the parting was like what with Aumerle being of the party that had sent off Bullingbrook. Aumerle replies that he couldn’t even bring himself to say farewell for to say it was to acknowledge that things were alright though they clearly weren’t. This prompts Richard to comment upon how Bullingbrook made a display of his affection for the English common folk before departing, and of how the common English folk reciprocated that affection as if Bulllingbrook and not Richard was England’s sovereign. Green, one of Richard’s trusted men, diverts Richard’s attention to the rebellion in Ireland, arguing that Bullingbrook’s exile should make his popularity a non-issue. Richard agrees and presently he mentions the strategies he’ll have to employ to raise revenues for the wars in Ireland. At this point, Bushy, another one of Richard’s trusted men, appears to report of John of Gaunt’s sudden illness and of his request to have a word with Richard. Richard is eager to see his uncle. And more than that he hopes that his uncle’s death will be speedy, allowing Richard to finance his war in Ireland with his uncle’s fortunes.