It is the early 1400s. Henry IV has died, and his son--the young King Henry V--has just taken over the throne. The situation is tense. Several bitter civil wars have left the people of England restless and dissatisfied. Furthermore, in order to gain the respect of the English people and the court, Henry must live down his wild adolescent past.

The Archbishop of Canterbury, worried over impending legislation that would effectively rob the Church in England of its power and wealth, convinces Henry V to forego this pursuit in favour of laying claim to France.

Because Henry has distant roots in the French royal family, and because the interpretation of ancient land laws varies from country to country, (Armed with a legal technicality) Henry lays claim to certain parts of France. The Dauphin's insulting response-sending an ambassador with a gift of tennis balls-convinces Henry that the French will only respond to war; thus, he arranges for an army to invade France. However, rebellion has always seemed to follow when the king's away, and Henry makes certain that he leaves behind enough troops in England to quell any potential uprising. That leaves him with a relatively small invasion force.

Henry's decision trickles down to affect the "little people" he rules. On the seedy side of London, some of the king's old friends--whom he rejected when he rose to the throne--prepare to leave their homes and families. Bardolph, Pistol, and Nym are common lowlifes and part-time criminals, on the opposite end of society from their royal former companion. As they get ready, they remark on the death of Falstaff, an elderly roustabout who was once King Henry's closest friend.

Just before his fleet crossing the Channel, Lords Cambridge, including a former friend, Scroop., and Grey are discovered to be conspiring to assassinate Henry (paid for by the French). Henry makes a very public example of all three, arresting them in person and seeing to their execution.

The army then lays siege to Harfleur, capturing it after heavy losses in battle with the city's defenders. . Among the officers in King Henry's army are men from all parts of Britain, such as Fluellen, a Welsh captain. As the English advance, Nym and Bardolph are caught looting and are hanged at the stern king's command.

Henry attempts to take his army out of France before the onset of winter; however, now the French are certain that they can teach the young king a humiliating lesson on the field of battle. Henry is resolute, nonetheless. If the French want a decisive battle, they will have it.

The final showdown of the war comes at the famous Battle of Agincourt, at which the English are outnumbered by the French five to one.

While in camp, Henry disguises himself as a common soldier in order to mingle with his troops before the battle. There he talks candidly with his men, and they with him. The men may be leery of their king, but their willingness to battle the French army is undaunted. The next day at Agincourt, Henry makes the stirring St. Crispin's Day speech, knowing his army is outnumbered five to one. Aided mightily by the longbows of his archers, Henry makes the day a rout for the French. The French must now sue for peace, which Henry will grant-completely on his own terms, of course. According to the terms of the Treaty of Troyes, Henry will marry Princess Katherine of France and will be named as heir to the French throne. England and France will thus be united in peace.