SCENE I. The palace in London.
Enter King Henry, Lord John of Lancaster, Earl of Westmoreland, Sir Walter Blunt and others. King Henry reflects on the recent civil wars that have prevented him from joining in on the crusades in Jerusalem. Looking forward to this, Henry asks the Earl of Westmoreland if the most recent convening of the council has made any progress towards this end.
Unfortunately, Westmoreland informs him that war has broken out on two fronts – one with the Welsh rebels and one with the Scottish. Westmoreland tells Henry that the Welsh rebel leader Owen Glendower has defeated Edmund Mortimer in battle, killed thousands of his soldiers and has taken him prisoner. On the Scottish front he bears outdated news; he tells the King that Harry Percy, nicknamed Hotspur, has engaged Archibald Earl of Douglas in battle. King Henry tells him that Sir Walter Blunt has already informed him that Hotspur has won and has taken a large sum of prisoners, including many important rebel individuals. The King considers Hotspur’s achievements and compares them to his son's, who wastes most of his time partying with provincial scoundrels.
Hotspur will only, however, hand over the prisoner Mordake Earl of Fife to the King; he will not hand over the rest, which the King has right to. Westmoreland estimates that Hotspur’s uncle, the Earl of Worcester, has prompted Hotspur’s behavior. Henry states that he will have to hold off the crusades. He tells them that he will hold court next Wednesday at Windsor castle to determine the cause of Hotspur’s behavior.
SCENE II. An apartment of the Prince’s in London.
Enter Prince Henry and Sir John Falstaff. Falstaff is a fat, old knight; he is a thief and his moral policy is opportunism. Falstaff asks Prince Henry, nicknamed Hal and Harry, the time of day. Henry makes fun of him for being a fat, old drunkard knight that ought not to have any concern for the time of the day. The two converse and by and by, Poins, nicknamed “Ned,” enters.
Poins notifies the two that a robbery has been planned for the following morning by himself and friends Gadshill, Peto and Bardolph. He requests that the two join them; Falstaff agrees to partake but Henry refuses protesting that he is not a thief. Poins asks Falstaff to leave him and Henry alone so that he can persuade him to join. Falstaff leaves.
Alone, Poins tells Henry of his plot to pull a joke on Falstaff, Gadshill and the others. They will detach from the party, pretending to ditch them, and after Falstaff and the others have done the robbery, Henry and Poins in guise shall rob them. The jest will be, when they inquire what happened, Falstaff’s fabrications about how they were robbed. Henry agrees and Poins exits.
Alone, Henry talks to himself and divulges his reasons for hanging around such low-lives. Apparently he is trying to cultivate a poor image so that when he adopts more noble ways he will be that much more impressive to everyone.
SCENE III. The palace in London.
Enter the King, Earl of Northumberland, Earl of Worcester, Hotspur, Sir Walter Blunt, and others. The King has summoned Hotspur to court so that he can explain wherefore he will not hand over his prisoners.
The King speaks to Hotspur; Worcester objects to the Kings threatening language. The King does not much appreciate this and orders him out of the room. Northumberland and Hotspur then start to explain to the King that the refusal was not meant as an act of insolence. Hotspur explains to the King: just as the battle ended an effeminate courtier arrived with the King’s demands for the prisoners. In the heat of the moment, offended by the arrogance of such a man, he spurned him and sent him away.
King Henry, however, does not think this explanation sufficient; he points out that Hotspur still denies him his prisoners and will only turn them over if Hotspur's brother-in-law, Mortimer, is bought back to England. He calls Mortimer a traitor for marrying Glendower's daughter, among other things, to which Hotspur defends Mortimer's honor but only ends up offending the King. Angry, the King forbids Hotspur to say Mortimer’s name and exits with Sir Walter Blunt and attendants.
Worcester reenters whereupon Hotspur gives an infuriated speech which, throughout, Northumberland and Worcester have trouble quieting. He suggests that the King may have ulterior motives in refusing to ransom Mortimer; for, before Richard II was illicitly disposed of by Henry, he had named Mortimer heir to the throne, and thus Mortimer’s claim to it may be stronger than Henry’s.
By and by Worcester manages to calm Hotspur down and explains that the Percy family has devised a plan to enact an insurrection. He explains that the Percy’s must seek alliance with the forces in Scotland and Wales; that, for now, he must give his prisoners back without demands, and that he is to beseech the Earl of Douglas, the leader of the Scottish rebellion, and establish an alliance with him. Northumberland will seek alliance from the Archbishop of York, and Worcester will go to Wales to discuss campaign strategy with Glendower and Mortimer.