In the English camp on the night before the battle, the king tells his brother Gloucester that he is worried about the outcome of the battle. When Sir Thomas Erpingham enters, the king, on an impulse, borrows Erpingham's cloak and is thus no longer identifiable as the king. He sends the others out to "commend [him] to the princes in our camp" and, since he wishes "no other company," he asks to be left alone to "debate" with himself.
Pistol enters and does not recognize Henry; he extols the king and asks the "young man" his name, and Henry tells him that his name is "Harry, le Roy." When Pistol discovers that he is a Welshman and knows Fluellen, he tells him that he plans to fight Fluellen. "Harry" warns him he might be defeated, and Pistol becomes so incensed that he insults "Harry" with a vulgar gesture and leaves. As Henry steps aside, Fluellen and Gower enter, unaware of the king's presence. Fluellen is angry with Gower for speaking his name too loudly, afraid that the French might have overheard it. Gower maintains that "the enemy is loud" and cannot hear him; in order to end the argument, Gower promises to speak lower and they exit. The king remarks that Fluellen is odd, but that he is a good soldier.
Next, three common soldiers, John Bates, Alexander Court, and Michael Williams, enter. Henry, unrecognized, tells them he serves under Sir Thomas Erpingham. Bates asks him if he thinks that the king should be told how bleak the situation really is. Henry says no, that the king is "but a man," as they are, and if he exhibited fear, he would discourage the army. Bates personally thinks that the king would prefer to be back in London, but Henry disagrees; he believes that the king is content to be where he is. Then Bates says that the king should be ransomed to save the lives of the men in the army. Henry responds by saying that he himself would not want to leave his king alone to fight the battle because of the king's "cause being just and his quarrel honorable."
Williams is unsure of the justness of the king's claim. Bates does not think it matters; if it is unjust, the guilt is upon the king's head and they will not have to share in the blame. When Williams suggests that those who die "unprovided" (unrepentant) will be a burden upon the king's conscience, Henry responds by saying that all who go to battle should be spiritually prepared, but that the king is not responsible to God for their deaths.
When the discussion returns to the king's ransom, Henry says he overheard the king say it would never happen; Williams jokes that it could happen after they are all killed and they would not know the difference. After another exchange of quips, in which Henry intimates that if times were different, he might be angry at Williams, Williams takes up the idea and challenges "Harry" to a fight if they should both survive the battle. They agree to exchange gloves and wear them in their caps so they can find each other the next day. Bates calls them both fools and urges them to be friends, for there are plenty of Frenchmen for them to fight.
After the three soldiers leave, Henry is left alone with his thoughts. He talks about the custom of blaming everything upon the king and concludes that a slave has a better life than a king, for he can sleep soundly at night and not worry about affairs of state.
Sir Erpingham enters, finds the king, and tells him that his associates are waiting for him. He leaves, and alone once more, Henry prays to God, asking Him to fill his soldiers with courage. He also asks God not to recall the guilt of Henry's father concerning the death of Richard II because he has already made reparations and plans to do more.
Henry's brother Gloucester enters, and the king leaves with him.
