Scene 1

Hotspur, Worcester, and Douglas are camped near Shrewsbury. A messenger arrives with letters indicating that Hotspur's father is ill and will not be joining in the rebellion. Worcester worries that this loss will hurt their cause. Hotspur, on the other hand, thinks that they may win more glory for defeating the king with a smaller force. He will not be deterred from his plans.

Sir Richard Vernon enters with more news. The king's forces are marching toward Shrewsbury, and the king and prince will join them soon. Hotspur refuses to be concerned. Vernon also relates that Glendower cannot raise his army fast enough to arrive for the confrontation. Hotspur merely remarks that they will “muster speedily” and “die merrily.”

Scene 2

Falstaff marches to war. He sends Bardolph off to find wine and then talks to himself about how he has raised his brigade from the poorest, most ragged, most down-and-out men in the area. They are a sad bunch who simply want their pay, and they lack any characteristics of trustworthy soldiers. Harry and Westmoreland enter. Harry is not impressed by the brigade of “pitiful rascals,” but Falstaff says they will make “food for powder” well enough.

Scene 3

At the rebel camp, Hotspur is determined to fight the king that very night against Worcester's advice. Vernon seconds Worcester. Their forces are not yet ready for battle. Douglas accuses Worcester and Vernon of “fear and cold heart.” 

Sir Walter Blunt arrives with a message from the king. Henry desires peace. He will pardon the rebels if only they name their griefs so that he can make things right. 

Hotspur replies that the king is not good at keeping his promises. Hotspur's family once helped Henry, thinking that he only meant to return to England to regain his title and property. Instead, he deposed Richard II, the current king. The Percy family fought beside him, but Henry no longer seems to remember this. He does not treat the Percys with respect but has disgraced them and broken his oaths to them. Hotspur tells Blunt that in the morning Worcester will go to the king with the rebels' final answer.

Scene 4

The Archbishop of York is nervous. He sends some letters by Sir Michael and fears that the rebels will fail in their attempt. Hotspur does not have enough power against the king's forces. Now the Archbishop wants to “prevent the worst,” probably for himself since he has supported the rebels, so he writes to friends who may be able to help.