Here is a short plot summary of Henry IV Part 1:
Henry Bolingbroke has usurped his cousin, Richard II, to become King of England. News comes of a rebellion in Wales, where his cousin, Edmund Mortimer, has been taken prisoner by Owen Glendower, and in the North, where Harry Hotspur, the young son of the Earl of Northumberland, is fighting the Earl of Douglas.
The king’s problems mount up and he is forced to postpone his proposed participation in a crusade. Moreover, his heir, Henry, known as Hal, shows no interest in princely matters and spends all his time in the London taverns with disreputable companions, particularly one dissolute old knight, Sir John Falstaff.
Falstaff will do anything to finance his eating and drinking. He carries out a robbery with two of hisfriends but Hal and Poins rob them in turn. Hal protects Falstaff from the law and returns the money to the victims.
Although Hotspur has been forced to agree to support the king he joins a plot with his father and his uncle, Worcester, to support Glendower, Mortimer, and Douglas against the king.
Hal returns to the court, makes his peace with his father, and is given a command in the army that is preparing to meet Hotspur. Falstaff has also been given a command but he has taken bribes and filled his ranks with beggars instead of recruiting able men. The King offers to pardon Hotspur if he will withdraw his opposition. Glendower’s troops and those of Northumberland have been unable to contact Hotspur and Worcester withholds the King’s offer from Hotspur and the battle of Shrewsbury begins.
Falstaff’s conduct in the war is disreputable and behaves in a cowardly way, while Hal saves his father’s life in combat with the Scotsman, Douglas. He encounters Hotspur, who is killed. Falstaff, having feigned death to avoid injury, claims to have fought and killed Hotspur. The King’s army triumphs over the rebels and Worcester is condemned to death. Hal frees Douglas while Henry takes his troops to continue the war against Mortimer and the Welsh, and the remnants of the Northumberland forces.