Hal, wayward prince and heir to the English throne, is crowned King Henry V after his tyrannical father dies. Now the young king must navigate palace politics, the war his father left behind, and the emotional strings of his past life.
Henry V (Timothee Chalamet) is a young prince in 15th century England. His father does not respect him and chooses his younger brother to be king, but when his brother and father die, he is made king anyway. The threat of war with France looms, and Henry does not know who in his court he can trust, so he brings in his good friend Falstaff (Joel Edgerton). Eventually France sends an assassin, so England goes to war. Henry manages to win the major battle, though Falstaff dies, and in his deal with France is married off to the King’s daughter Catherine (Lily-Rose Depp), who tells him that France never sent an assassin. Henry confronts his advisor, William (Sean Harris), who admits it was a fake attempt in order to ensure England took France, gaining the peace Henry wanted. Henry kills William and makes Catherine promise to always be honest with him.
Henry Prince of Wales (called “Hal” by his close friends) is the emotionally distant eldest and wastrel son of King Henry IV of England. Hal is uninterested by his father’s war policies, and spends his days drinking and jesting with companion John Falstaff in Eastcheap. His father summons Hal and informs him that Hal’s younger brother, Thomas, will inherit the throne instead of Hal. Thomas is sent to subdue Hotspur’s rebellion, but is upstaged by the arrival of Hal, who engages Hotspur in single combat. The sword fight descends into an armoured fistfight and Hal kills Hotspur with a dagger. Although this decides the battle without further conflict, Thomas complains that Hal has stolen all the glory. Not long after, Thomas dies in further battle in Wales.
Henry IV dies in his bed with Hal present, and Hal is crowned King Henry V. Hal is determined not to be like his father, opting for peace and conciliation despite his actions being seen as weakness. Meanwhile, the Dauphin of France sends a ball, an insulting and emasculating coronation gift to Hal; however, Hal chooses to see this as a positive reflection of his own youth.
Hal takes a walk with his young sister Philippa, now the Queen of Denmark, in a green field below a castle. She asks after his well-being and he tells her he wants to bring an end to the unrest in the kingdom then tells him that she could feel the calm he desires at the coronation celebration dinner the previous evening. She adds too that she believes the nobles wish him well in that vision of peace, but cautions him that nobles in any royal court have their own interests in mind and will hold from revealing their full truths.
A captured assassin is interrogated in French by Hal and claims to be sent by King Charles VI of France to assassinate Hal. The English nobles Cambridge and Grey are approached by French agents, hoping to induce them to the French cause, their trust in the new young king waivers and they then approach Hal’s Chief Justice, William Gascoigne with their concerns. William advises the young king that a show of strength is necessary to unite England, so to prove his competency, Hal declares war on France and has Cambridge and Grey beheaded.
The English army set sail for France, with Hal at the forefront and Falstaff as his captain. After successfully taking Harfleur, they continue on the campaign, but are followed by the Dauphin, who repeatedly tries to provoke Hal. The English advance parties stumble upon a huge French army gathering to face them. Dorset advises Hal to retreat, due to the superiority of the French, but Falstaff proposes a false advance, luring the French to rush forward into the mud, where they will be weighed down by their heavy armor and horses. They will then be attacked by the English longbowmen and surrounded by a large flanking force hidden in the nearby woods.
Hal goes to the Dauphin and offers to fight in single combat to decide the outcome of the battle, but the Dauphin refuses. The Battle of Agincourt commences, with Hal in the thick of the fighting. The plan works and the outnumbered English army overpowers the French, though Falstaff is killed on the front lines. The Dauphin enters the fray to challenge Hal, but is humiliated and easily defeated.
Following the decisive victory, the English continue deeper into France. Hal reaches King Charles VI, who offers his surrender and the hand of his daughter Catherine. Hal returns to England with his new wife for the celebrations. He comes to her room to have a conversation and it quickly turns into a frank one that shows her strength of character and also causes him to question his military decisions because she challenges Hal’s reasons for invading France. Hal realizes that the supposed French insult and acts of aggression against England were staged and caused by his chief Justice Gascoigne to goad Hal into war. Hal confronts Gascoigne and upon confirming his suspicions, proceeds to fatally stab him. He then returns to Catherine, asks her to always speak the truth to him, and takes both her hands in his. Meanwhile outside the palace, people cheer “King Henry, King Henry” to celebrate his victory over the French.
In the 15th century, Henry V (Timothee Chalamet) is the ne’er-do-well son of King Henry IV (Ben Mendelsohn) who spends most of his days drinking and carousing with his friend John Falstaff (Joel Edgerton). Henry IV is ill and dying, and declares that his younger son Thomas (Dean-Charles Chapman) shall be king upon his death instead of Henry. Henry wants nothing to do with it anyway.
When a rebellion led by Percy (Tom Glynn-Carney) rises up against Henry IV, the very young Thomas leads a battalion to fight it. Henry V, disliking war and fearing for his brother, implores him to let him challenge Percy to a one on one duel to avoid bloodshed. Thomas does not want to, but Percy accepts and Henry kills him in a duel, quashing the rebellion, leaving Thomas feeling upstaged. Later, William Gascoigne (Sean Harris), one of the king’s most right-hand advisers comes to Henry to tell him that Thomas continued his battalion and died in battle, and the king is dying imminently – he dies and Henry becomes king.
At his coronation, he is given gifts from all over the world, one of which he re-gifts to his close cousin Cambridge (Edward Ashley). His sister Phillipa (Thomasin McKenzie) warns him to be wary of those in his inner circle. The gift from France is a ball, which his court feels is mocking him and calling him a child – various people around Henry keep talking up a war with France, which he has no interest in. Eventually, William brings to him a French assassin who says he was sent by the King of France to kill Henry. Meanwhile, Cambridge and another ally go to William with their concerns about Henry’s leadership. Henry has them beheaded and declares war with France.
Unsure of who he can trust, he asks Falstaff, a former soldier, to join his council. They take their army to France, taking early strongholds. The Dauphin (Robert Pattinson), Prince of France, meets Henry for a summit, where instead of surrendering he viciously insults and taunts Henry. Later, The Dauphin executes several British children in a message to Henry. Enraged, he orders all the French prisoners executed, but Falstaff talks him down.
The British come upon a massive French army. Henry is advised to turn around and retreat as the odds are against them – but Falstaff believes they can win, because rain is expected, and the French will have to come downhill, causing them and their horses to slip in the mud with their armor dragging them down. Henry decides if it rains, they will go to war, which it does. Falstaff decides to lead the first wave out, which Henry doesn’t want him to do, but Falstaff says because it is his plan he must lead the troops out.
Henry meets one more time with The Dauphin, and asks him to fight him one on one to spare the lives of their men. The Dauphin wants an unequivocal surrender from Henry, and so the battle begins. When it’s time for the second wave, Henry gives a rousing speech and leads them into battle. Once much carnage has taken place, The Dauphin enters and accepts the battle-worn Henry’s challenge. When he attempts to fight him, his armor weighs him down into the mud, and Henry signals to his men to take him, which they do, killing him. After winning, Henry finds Falstaff’s body on the battlefield.
Henry meets with the King of France, he surrenders. In order to make peace between their nations, he offers Henry the hand of his daughter, Catherine (Lily-Rose Depp). Before they get married, Catherine roughly questions Henry on why he made all the bloodshed of war happen – he tells her that his father tried to assassinate him, which she denies. He confronts William, realizing that he faked the assassination attempt in order to get Henry to take France. William, on his knees, says he got Henry a united England like he wanted. Henry stabs him, killing him. He returns to Catherine and asks her to promise to always be straight with him, and she agrees.