Note: Henry IV, Part 1 has two main plots that intersect in a dramatic battle at the end of the play. The first plot concerns King Henry IV, his son, Prince Harry, and their strained relationship. The second concerns a rebellion that is being plotted against King Henry by a discontented family of noblemen in the North, the Percys, who are angry because of King Henry’s refusal to acknowledge his debt to them. The play’s scenes alternate between these two plot strands until they come together at the play’s end.

When the play opens, military news interrupts the aging King Henry’s plans to lead a crusade. The Welsh rebel Glyndˆwr has defeated King Henry’s army in the South, and the young Harry Percy (nicknamed Hotspur), who is supposedly loyal to King Henry, is refusing to send to the king the soldiers whom he has captured in the North. King Henry summons Hotspur back to the royal court so that he can explain his actions.

Meanwhile, King Henry’s son, Prince Harry, sits drinking in a bar with criminals and highwaymen. King Henry is very disappointed in his son; it is common knowledge that Harry, the heir to the throne, conducts himself in a manner unbefitting royalty. He spends most of his time in taverns on the seedy side of London, hanging around with vagrants and other shady characters. Harry’s closest friend among the crew of rascals is Falstaff, a sort of substitute father figure. Falstaff is a worldly and fat old man who steals and lies for a living. Falstaff is also an extraordinarily witty person who lives with great gusto. Harry claims that his spending time with these men is actually part of a scheme on his part to impress the public when he eventually changes his ways and adopts a more noble personality.

Falstaff’s friend Poins arrives at the inn and announces that he has plotted the robbery of a group of wealthy travelers. Although Harry initially refuses to participate, Poins explains to him in private that he is actually playing a practical joke on Falstaff. Poins’s plan is to hide before the robbery occurs, pretending to ditch Falstaff. After the robbery, Poins and Harry will rob Falstaff and then make fun of him when he tells the story of being robbed, which he will almost certainly fabricate.

Hotspur arrives at King Henry’s court and details the reasons that his family is frustrated with the king: the Percys were instrumental in helping Henry overthrow his predecessor, but Henry has failed to repay the favor. After King Henry leaves, Hotspur’s family members explain to Hotspur their plan to build an alliance to overthrow the king.

Harry and Poins, meanwhile, successfully carry out their plan to dupe Falstaff and have a great deal of fun at his expense. As they are all drinking back at the tavern, however, a messenger arrives for Harry. Harry’s father has received news of the civil war that is brewing and has sent for his son; Harry is to return to the royal court the next day.

Although the Percys have gathered a formidable group of allies around them—leaders of large rebel armies from Scotland and Wales as well as powerful English nobles and clergymen who have grievances against King Henry—the alliance has begun to falter. Several key figures announce that they will not join in the effort to overthrow the king, and the danger that these defectors might alert King Henry of the rebellion necessitates going to war at once.

Heeding his father’s request, Harry returns to the palace. King Henry expresses his deep sorrow and anger at his son’s behavior and implies that Hotspur’s valor might actually give him more right to the throne than Prince Harry’s royal birth. Harry decides that it is time to reform, and he vows that he will abandon his wild ways and vanquish Hotspur in battle in order to reclaim his good name. Drafting his tavern friends to fight in King Henry’s army, Harry accompanies his father to the battlefront.

The civil war is decided in a great battle at Shrewsbury. Harry boldly saves his father’s life in battle and finally wins back his father’s approval and affection. Harry also challenges and defeats Hotspur in single combat. King Henry’s forces win, and most of the leaders of the Percy family are put to death. Falstaff manages to survive the battle by avoiding any actual fighting.

Powerful rebel forces remain in Britain, however, so King Henry must send his sons and his forces to the far reaches of his kingdom to deal with them. When the play ends, the ultimate outcome of the war has not yet been determined; one battle has been won, but another remains to be fought (Shakespeare’s sequel to this play, Henry IV, Part 2, begins where Henry IV, Part 1 leaves off).