At the rebel camp near Shrewsbury, Hotspur and Douglas exchange compliments about each other's martial prowess. Then a messenger arrives with a letter from Northumberland, Hotspur's father, saying that he is sick and cannot come. He will not give the command of his forces to anyone else either. But he urges the rebels to proceed without him. They have little choice in the matter, since the King is fully informed of their activities.
Worcester believes the loss of Northumberland to be a great blow, but Hotspur is determined to make the best of it. He argues that it is better that they do not risk all their forces in one battle. If they should not prevail, they will have a stronghold (Northumberland) to fall back on. Douglas agrees. But Worcester is not convinced. He thinks the absence of Northumberland may cause rumors to spread that Northumberland does not support their enterprise. This could prove devastating to their cause. Hotspur argues the opposite, that people will think that if the rebels, even without Northumberland, can make headway against the King, the whole kingdom must be weak and ready to fall.
Sir Richard Vernon arrives and reports that the armies of Westmoreland, Prince John, and the King himself are marching toward Shrewsbury. Hotspur inquires contemptuously about Prince Hal, and Vernon replies that he saw him readying for battle and looking like a formidable warrior, showing excellent horsemanship.
This praise of the Prince angers Hotspur. He invokes the battle to come, and promises he will fight with Prince Hal until one of them drops down dead. He eagerly awaits the arrival of Glendower's army.
But Vernon gives him more bad news. Glendower cannot raise an army in sufficient time to take part in the battle. Worcester and Douglas are disturbed by this news, but once again, Hotspur tries to put a brave face on it.
Worcester and Douglas are more pessimistic (one might say realistic), about their prospects of success than Hotspur, who is eager to fight no matter what the odds. The absence of Northumberland through sickness suggests a wider symbolic significance, as Hotspur unwittingly reveals: "This sickness doth infect / The very lifeblood of our enterprise (lines 228-29). This implies that there might be something wrong with the nature of the enterprise itself. It may not be the just war the rebels claim it to be. The suggestion of sickness at the heart of the rebel cause tends to undermine Douglas's earlier reference to Hotspur as "the king of honor." This is certainly Hotspur's view of himself, but it may be that Hotspur is not quite as honorable as he thinks he is. Personal pride and ambition play a bigger role in his motivation than he cares to admit.
Vernon's speech in praise of Prince Hal continues to prepare the audience for the transformation in Hal that has already been signaled. It is particularly forceful coming as it does from one of the Prince's enemies. Prince Hal is about to lay claim to his true status as the heir to the throne, the future Henry V who will win fame and immortality in English history at the battle of Agincourt in France (as Shakespeare shows in Henry V).