Henry V is a historical play. It is based on real events.
Henry V is King of England. He also believes he has a right to be the next king of France, and sends an official notice to the Dauphin (the French prince) saying that he intends to claim the throne. Henry is encouraged in his claim by the Archbishop of Canterbury and other leaders of the Church of England, who are worried about a proposed government bill which would transfer a lot of Church property to the state. They hope that a war with France will divert Henry's attention away from the matter! After a lot of thought, legal advice from two churchmen (who back up his claim to France) and consideration of how to deal with the potential danger Scotland would be to England while he is away, Henry makes the decision to invade France.
When the French prince insults him by sending him a gift of 'treasure' which turns out to be tennis balls and a message mocking Henry's ability to rule, and then rejects his claim to the throne, Henry prepares for war with France.
Although the French are not too worried about the threat of war with England, they pay three of the English nobles to kill Henry. Even Scroop, Henry's best and trusted friend, is involved. The plot is discovered and Henry is angry and upset. The three friends are cunningly tricked by Henry into admitting their crimes and are condemned to death.
As the French are waiting for the invasion, they laugh about how easy it will be to hold back the small English army. Few people worry that Henry is a real threat. Very soon, however, the English capture Harfleur, an important French town, and French pride is wounded. They are angry, and call up their full army to crush the English.
Meanwhile, the French king has offered his daughter Katherine to Henry as his wife. Katherine tries to learn English from her maid in preparation for her married life.
The two armies camp and prepare for battle near a village called Agincourt. On the night before the battle, we see two very different armies. The French are so confident that they can't wait for the next day, making bets on how many prisoners they will take and wondering if there will be a fight at all. They have 25,000 soldiers to Henry's 5,000. The battle is savage and brutal, and there are terrible crimes committed by both sides.
The English are exhausted, but watchful and tense. Henry borrows a cloak to disguise himself and goes to talk to some of the common soldiers about their thoughts on the battle - he is conscious of the great responsibility on his shoulders and prays to God to help him. Just before the battle, Henry gives a rousing speech, telling his men that this day will go down in history.
The battle is savage and brutal, and there are terrible crimes committed by both sides.
The English win, suffering very few deaths compared to the huge number of French casualties. Henry orders for prayers to be said for the dead, then returns to England in triumph before going back to France to claim the kingdom. The Princess Katherine agrees to be Henry's wife and the king of France blesses the subsequent marriage with the hope that it will lead to peace between the two countries.