King Henry IV delays his plan to wage a crusade in the Holy Land when he learns of unrest throughout his kingdom. The Earl of Westmorland informs him that nobleman Edmund Mortimer has been taken prisoner by the Welsh nobleman Owen Glendower after losing a thousand men in battle.

More positively, Henry Percy, nicknamed Hotspur, put down a rebellion in the North, taking prominent hostages in battle. The king praises Hotspur while lamenting that “riot and dishonor stain the brow” of his own son, also named Henry (1.1.84). However, Hotspur refuses to turn over the hostages to the king. The king calls a meeting at Windsor to assess the situation.

At a tavern, Prince Hal and Sir John Falstaff taunt each other. Falstaff and his companions are thieves, and Falstaff asks the prince to be merciful to thieves when he is king. Falstaff jokes that he would get a good reputation if he knew where to buy one. Ned Poins enters and informs them about a group of pilgrims bound for Canterbury; he suggests they rob them. Falstaff agrees and departs. Poins suggests he and Hal let Falstaff and his associates rob the pilgrims then rob them in turn.