When the play opens, King Henry has called the Percies — Northumberland, Worcester, and Hotspur — to the palace. He demands to know why the ranking Scottish prisoners taken by Hotspur have not been turned over to him. The Percies are furious with Henry's seeming arrogance; they deeply resent the fact that this man whom they helped to the throne should demand absolute obedience from them. Thus, they begin to plot their revolt.
Meanwhile, in the comic subplot, Prince Hal and his boon companions make plans to rob a group of travelers in order to play a practical joke on their beloved, blustering cohort, Sir John Falstaff. The joke almost backfires, but Falstaff manages to barely escape, and back at the tavern, he emerges triumphantly as the comic hero of the escapade. The merrymaking is interrupted, however, when Prince Hal is called back to court on urgent business.
Hotspur's threats are serious; meeting with Worcester, Mortimer, and Glendower at the residence of the Archdeacon in North Wales, the men plan a campaign against the royal forces; afterward, they plan to divide England into three parts. Momentarily, Hotspur is dejected that he cannot count on Northumberland's troops, but he reasons that perhaps the populace will be even more impressed when they realize that Hotspur accomplished his coup without Northumberland's help.
When he learns that Henry's royal army has set forth for battle, Hotspur is again worried — this time about the news that Prince Hal accompanies his father's troops as second in command. But deciding that his victory will seem even more miraculous if he can dispose of Hal personally, Hotspur vows to kill Hal himself, and his ardor and impetuosity is rekindled.
