In the prologue to Act 1, the Chorus enters and appeals directly to the audience to use their imagination to create the world of the play they are about to see. The Chorus apologises that it is impossible to tell the story of 'two mighty monarchies' going to war with just a few actors in a theatre. Therefore, the audience are encouraged to imagine 'the vasty fields of France', the soldiers that 'did affright the air' and the horses that printed 'their proud hoofs i’th’receiving earth'.

At the palace of King Henry V, the Archbishop of Canterbury and the Bishop of Ely discuss the money the church will lose if a new law is passed by Parliament. They believe Henry will forget about the new law if they help raise money to fund his claim to the French throne.

The Archbishop of Canterbury assures Henry that his claim to the French throne is legitimate. He urges him to call on the 'warlike spirit' of his ancestors and take back the throne that is rightfully his.

The French Ambassador enters with an enormous treasure chest, a gift for Henry from the Dauphin. The chest is full of tennis balls and Henry sends back a threatening message that he will turn the tennis balls into cannon balls that will destroy France and 'strike the Dauphin blind to look on us'.

In a prologue to Act 2, the Chorus tells the audience that the youth of England 'are on fire' and ready for war, while the French 'Shake in their fear'. The audience are warned that there are three English traitors (the Earl of Cambridge, Lord Scroop and Sir Thomas Grey), who have taken money from France to kill Henry. The Chorus asks us to imagine that we are in Southampton, waiting for the King to arrive, and to picture the sea voyage as he sails from Southampton to France.

Bardolph and Nym are talking about the coming war. Nym is angry because their friend Pistol has married his fiancé, Mistress Quickly. Pistol and Mistress Quickly enter and the former friends draw swords, but Bardolph breaks up the fight. The Boy runs in, saying that Falstaff, King Henry’s old drinking friend, is 'very sick'. They all agree that Falstaff is dying because 'the King has killed his heart' by abandoning him as a friend.

In Southampton, Henry talks to the three traitors (the Earl of Cambridge, Lord Scroop and Sir Thomas Grey). Henry tells a story about a drunk man who insulted him in public and he asks the traitors if he should forgive the man. The traitors say he should be punished 'lest example / Breed, by his suffrance more of such a kind'. Henry gives them each a document to read which contains proof of their plot and the traitors are taken off to prison.

The friends mourn the death of their beloved Falstaff. Nell describes his final moments: 'So a cried out, ‘God, God, God!’ three or four times.' Pistol, Nym and Bardolph decide they’ve done enough grieving and it’s time to set off to France to fight.

In France, King Charles worries about how close the English army is. His son, the Dauphin, dismisses his fears, thinking Henry is a 'vain, giddy, shallow, humorous youth' but Charles reminds him that Henry’s ancestors have humiliated France in the past. Henry’s ambassador, Exeter, enters with a warning that if the French don’t back down, Henry will come 'In thunder and in earthquake, like a Jove'. Charles says he’ll consider it but the Dauphin wants 'Nothing but odds with England'.

As Henry leads his troops into the 'breach', Pistol and Nym pull Bardolph back to avoid the fighting. 'I have not a case of lives' says Nym. Captain Fluellen, a Welshman, shouts at them to fight and chases them after the troops. Alone onstage, the Boy tells the audience that the Eastcheap Three have been stealing but he refuses to join in as it 'makes much against my manhood'.

In Act Three’s prologue, the Chorus asks the audience to use their senses to bring to life Henry’s sea voyage from Dover to the shores of Harfleur in France. We are also told to imagine we’ve just seen Henry reject a peace offering from France.

Henry gives a rousing speech to his army to urge them through the hole or 'breach' they’ve just created in the town wall at Harfluer saying to them 'Once more unto the breach, dear friends, / once more'. He tells them to 'imitate the action of the tiger' and fight with everything they’ve got; this will make even the farmers amongst them into noble men. He leads them on with one final shout: 'Cry ‘God for Harry, England, and Saint George!’'

Fluellen and three other Captains: Gower, MacMorris (an Irishman) and Jamy (Scottish), argue about the art of war.

Henry gives a threatening speech to the Governor of Harfleur, telling him to surrender or he could lose control of his troops who will then slaughter them, 'mowing like grass / Your fresh fair virgins and your flow’ring infants'. The Governor surrenders and Henry leaves Exeter in charge of Harfleur and leads his men back towards Calais in hope of rest.

At the French palace, Princess Katherine asks Alice, her lady-in-waiting, to teach her some words in English to prepare her for a possible marriage to Henry. Katherine says the English words foot and gown making them sound like offensive French words.

King Charles and the Dauphin discuss Henry’s advance through France. The rumour is that Henry’s men are exhausted and weak and Charles orders his troops to overcome them and capture Henry.

Bardolph has been caught looting from a church. Pistol argues with Fluellen for Bardolph’s life. Gower recognises Pistol as a well-known thief and when Henry arrives with his troops he agrees that his old friend Bardolph should be hanged. Montjoy then arrives with a warning from King Charles that the French will crush the English if they don’t retreat. Henry tips Montjoy money and says to reply that the English are tired but 'upon one pair of English legs / Did march three Frenchmen.'

At the French camp, the Dauphin and his Dukes are impatiently waiting. The Constable brags about his armour and the Dauphin brags about his horse 'I once writ a sonnet in his praise'. The others mock him and when the Dauphin leaves, the Constable tells Orléans he’s all words and will be useless in battle. They both agree that Henry is a fool and that his army are doomed.

In the prologue to Act 4, the Chorus tells the audience that the French are overconfident that they will beat 'The poor condemne`d English’ and King Henry has been visiting the camp trying to cheer up the English soldiers. The Chorus apologises again that the theatre is too limited to create the massive battle of Agincourt.

Henry walks around the camp in disguise to see how his men are feeling. Pistol talks to him and is full of praise for the king. Henry then meets a soldier, Williams, who says 'if these men do not die well, it will be a black matter for the king that led them to it'. Henry, still in disguise, defends 'the King’ but Williams doesn’t agree. they decide to meet again to settle their disagreement after the battle and swap gloves so they can find each other. Left alone, Henry describes the loneliness and difficulties of kingship saying ' O, hard condition, / Twin-born with greatness'.

At the enemy camp, the French are still confident. A messenger reports that the English are lined up and ready and the jester, Constable, jokes that they are lined up to die. They all then leave to fight.

At the English camp, we learn Henry’s Army is badly outnumbered. His commanders wish they had more men and Henry delivers a Patriotic speech to rouse his tired men, calling them 'We few, we happy few, we band of brothers' and saying that everyone will remember who fought with him on St. Crispin's Day. Montjoy comes back to offer them another chance to surrender but Henry refuses.

On the battlefield, Pistol captures a French soldier who begs for his life. Pistol demands money but can’t speak French so the Boy translates everything. When alone onstage, the Boy complains to the audience that Pistol is a nothing but a boaster 'The empty vessel makes the greatest sound' and that Nym has also been hanged for stealing. The Boy then heads back to where the rest of the young pages guard the camp.

Elsewhere on the battlefield, the French are losing badly, despite having more men. The Dauphin and his men are devastated and Bourbon orders the French soldiers back to battle: 'Shame and eternal shame, nothing but shame!'

Exeter tells Henry that the Earl of Suffolk and Duke of York have been killed. Exeter apologises for his tears but Henry admits he is also moved. Henry hears that the French are returning to the fight and orders his men to kill all the French prisoners.

The French have slaughtered all the young pages in the English camp. Henry is horrified: 'I was not angry since I came to France / Until this instant.' He repeats his order to kill the prisoners. Montjoy arrives and asks if the French can collect their dead. Henry asks if that means the English have won. Montjoy replies that it does. Fluellen reminds Henry that he was born in Wales and says he is proud to be his Kinsman. Williams enters, wearing King Henry’s glove in his cap. Henry decides to play a trick on him. He sends Williams away and gives his glove to Fluellen, saying that it belongs to a Frenchman and if anyone claims it, he is a traitor.

The Chorus delivers the final prologue by telling the audience about Henry’s journey to England and then his return to Calais. They describe 'How London doth pour out her citizens' for his victorious return and we learn that the Holy Roman Emperor visited England on 'behalf of France' to order peace. The Chorus then asks the audience to skip over these details and imagine Henry’s return to France to make his demands in person.

In the English camp, Fluellen tells Gower that Pistol insulted him for wearing a leek in his hat, a symbol of his Welsh patriotism. When Pistol enters, Fluellen forces him to eat it, saying 'if you can mock a leek, you can eat a leek'. Pistol then reveals that his wife, Mistress Quickly, has died and now he plans to go back to England and steal.

Henry woos Katherine. At the French palace, Henry meets with the French King and Queen to arrange the peace treaty. Their daughter Katherine is part of the negotiations. They meet and speak to each other, even though they struggle to understand each other’s languages. Henry apologises for his plain soldier talk but doesn’t give up. King Charles accepts all Henry’s demands and he and the Queen give Henry and Katherine their blessing.

The Chorus apologises again for the poor attempts of the playwright to tell this story in a 'little room confining mighty men.' The Chorus then fills the audience in on what happens after this play ends. We learn that, after Henry’s success in France, he and Katherine had a son who became Henry VI who unfortunately 'lost France and made his England bleed'.