(Before the main body of the play begins, we are greeted with a Prologue by Rumor. The actor who plays Rumor would be wearing a costume painted with tongues. Rumor is a semi-mythological personification of "gossip" and does not represent a "real" character in the play.)
Rumor introduces itself and tells us what its job is: from East to West, all across the world, it carries messages as fast as the wind. However, its messages are usually false and they often trick people into making bad mistakes. Rumor causes nations to get ready for war when no war is coming, and it makes people think that all is peaceful despite real danger and conspiracy. Since crowds are always quick to believe rumors and gossip, it never has any trouble doing its job.
Just now, Rumor is visiting a house in the north of England. This is the castle of the Earl of Northumberland, a powerful nobleman. Northumberland is part of a dangerous conspiracy to overthrow King Henry IV. The rebel army, led by Northumberland's son, young Hotspur, has just been defeated by the forces of the king. However, the gossip sweeping the countryside has the news backward. Rumor has come to tell Northumberland that his side has won and that his son, Hotspur, is still safe--both lies.
Rumor then disappears, and a messenger from the battle, Lord Bardolph, arrives at the Earl of Northumberland's house. Lord Bardolph has news from Shrewsbury, where the great battle is taking place. He tells Northumberland news that makes him very happy: King Henry has been wounded, his allies captured or killed, and the king's own son, Prince Hal, killed by Northumberland's son Hotspur. That means the rebels are victorious.
Then, however, another messenger arrives--Lord Bardolph's servant, Travers. Travers says he has even more recent news: the rebellion has lost and lost badly. Lord Bardolph does not believe him, but Travers is soon followed by a third messenger, Morton. Morton has very bad news indeed: the rebellion has lost, and Northumberland's son, Hotspur, has been killed by the king's son Prince Hal--not the other way around. When the rebel army saw that their leader Hotspur was dead, they turned and ran. Northumberland's brother and co-leader in the rebellion, the Earl of Worcester, has been taken prisoner by the king's forces, as has the Douglas, a Scottish leader who has been aiding the rebels.
Northumberland is heartbroken to learn this, and he vows to take a terrible revenge. Lord Bardolph and Morton calm him down, reminding him that he, his brother, and his son all knew the risks of war before they began.