On the battlefield at Shrewsbury, the fight is on between the army of King Henry and the forces of the Percy rebellion. The Douglas, the fearless leader of the Scotsmen, searches the battlefield for Henry himself. He meets Sir Walter Blunt, dressed like the king and acting as a decoy. The two fight, and the Douglas kills Blunt. Hotspur enters and identifies the dead Blunt as an impostor.

The two leave in search of the real Henry, and Falstaff appears, trying to avoid the heat of the battle. He encounters a breathless Harry, who has lost his sword. Harry asks Falstaff if he can borrow his. The cowardly Falstaff declines to give it up—if Hotspur is still alive, Falstaff does not want to be unarmed. Disgusted, Harry leaves, and Falstaff goes off in a different direction.

Harry reenters, now accompanied by his father, brother John, and Westmoreland. Harry is wounded but refuses to stop fighting and seek medical attention. He heads off with John and Westmoreland to fight, leaving Henry alone. The Douglas reenters, still seeking the king. Henry bravely meets the Douglas in single combat, although he knows that he can hardly hope to win: he is an old man, while the Douglas is a deadly fighter in the prime of his life. Harry reappears, and, seeing his father in danger, challenges the Douglas, whom he beats back so ferociously that the Douglas flees the field. Henry thanks his son with warmth and pride, saying he has at last regained his father’s respect, and Harry heads back into battle.

Hotspur enters and finds Harry alone. They identify one another, and both agree that it is time they fought to the death. In the heat of their battle, Falstaff wanders back in. The fighters do not notice him, but Falstaff cheers Harry on. The Douglas returns once again and attacks Falstaff. Falstaff falls down, pretending to be dead, and the Douglas leaves him where he lies.

Harry, meanwhile, has critically wounded Hotspur, who dies. Spying Falstaff lying on the ground as if dead, Harry eulogizes both and, vowing to come back and bury them, leaves. As soon as Harry is gone, Falstaff springs up and stabs the dead Hotspur in the leg. When Harry and John reenter, Falstaff, in his typical manner, claims that he fought a bloody battle with the wounded Hotspur after Harry left and finally finished him off. John and the dumbfounded Harry decide to settle the matter later. They hear the trumpets sounding retreat, and all return together to the base camp.

The battle is over, and Henry’s forces have won decisively. The rebel leaders are all dead or captured. Henry, who has discovered that the battle was triggered, in part, by Worcester’s intentional failure to deliver his offer of peace to Hotspur, orders Worcester and Vernon to be executed.

News arrives that the Douglas has been captured. Harry, asking his father for permission to handle the case, commands that the Douglas be set free in recognition of his valor and integrity. Henry, realizing that there are still powerful rebels left alive, makes plans to deal with them: he will send John and Westmoreland to York to deal with Northumberland and the archbishop, who he knows are up in arms against him. Meanwhile, Prince Harry, he says, will come with him to Wales to deal with Mortimer and Owain Glyndwr.

These very short, very busy scenes, which show us the progress of the battle at Shrewsbury, represent the main climax toward which the earlier portions of the play have been building. Nearly all the factions have finally been brought together in a single compressed, action-packed battle—marked by frenetically paced entrances and exits and clashes in single combat.

Falstaff’s battlefield interpretation of honor in this final section of the play provides both amusement and food for thought. When he stumbles across the body of Sir Walter Blunt (slain, ironically, because he is thought to be King Henry), his immediate comment is: “Sir Walter Blunt. There’s honour for you. Here’s no vanity” (V.iii.32–33). His jab about “vanity” is ironic. Falstaff seems to be commenting sarcastically on the extreme vanity, or folly, of Blunt’s death—if “honor” is what has led to his lying cold on the ground, then “honor” seems utterly useless.

Falstaff’s thoughtful linking of honor with death and his preference for life are vividly illustrated in the next scene, when Falstaff seems to die and then return to life. In some respect, Falstaff enacts a bizarre and playful mockery of war and death: in addition to -carrying around a bottle of wine where his gun should be, he pretends to be killed honorably in battle, receives a eulogy from Harry, and then rises up, pretending that he has conquered a nobleman. Not even the danger of the field can stop him from punning. With his inimitable Falstaffian logic, he defends his own honor in these actions: “The better part of valour is discretion, in the which better part I have saved my life” (V.iv.117–118). Falstaff’s views on honor, though they are unlike those of the noblemen fighting and dying on the battlefield, are oddly convincing—perhaps especially so because, unlike so many of the noblemen, Falstaff ends up alive.

Harry resolves two of his own important conflicts during this battle. First, he finally resolves the tension between himself and his father. When he rescues Henry from the attack of the Douglas, Henry’s response is complex but wholly approving. Not only is he proud of his warlike son, but he also seems to have been genuinely concerned that his son did not care about him (“Thou hast redeemed thy lost opinion, / And showed thou mak’st some tender of my life” [V.iv.47–48]). Harry responds in equally heartfelt terms—“O God, they did me too much injury / That ever said I hearkened for your death”—that further distinguish him from Hotspur; for while Hotspur seeks to overthrow Henry, Harry seeks to preserve him (V.iv.50–51).

Second, Harry finally confronts Hotspur, and the two engage in their long-anticipated duel. Harry’s commanding announcement when he faces Hotspur that “[t]wo stars keep not their motion in one sphere” shows his perception of them as rivals who cannot coexist (V.iv.64). While both men idealize valor, in the end, they seem to have somewhat different approaches to the question that Falstaff raises earlier about the relationship between honor and death. Even as he is dying, Hotspur mourns more for his glory than for his life: “I better brook the loss of brittle life / Than those proud titles thou hast won of me” (V.iv.77–78). But Harry, contemplating Hotspur’s corpse, brings forth a famous contemplation on the humility enforced by death:

No matter how great one’s life, one’s honor can never outlast one’s life, Harry states, since death reduces one to so little.

Henry’s division of his forces at the very end of the final scene, as he announces his plan to send John and Westmoreland up to fight Northumberland and his own intent to take Harry to Wales to put down Glyndwr, leaves the door wide open for the play’s sequel, 2 Henry IV, in which these dangling plot threads are resolved. In many ways, 1 Henry IV is a play without a conclusion. Critics often refer to the two Henry IV plays as a single play with ten acts; under that interpretation, the real play is now only half over.