On the highway near Gadshill, Falstaff frets because Poins has hidden his horse away somewhere. He complains to Prince Hal, who teases him about it. Bardolph and Gadshill enter and announce that the travelers who are to be robbed are approaching down the hill. The Prince and Poins make an excuse to separate themselves from the others, saying they will act as back-up if the travelers manage to escape the first attack. Poins tells Falstaff where he can find his horse; he has hidden it behind a hedge.
Poins and the Prince exit. The robbery takes place. Then, following their plan, the disguised Prince and Poins waylay the robbers, who all run away, leaving the spoils of the robbery behind. Falstaff manages one or two blows, and then he also runs away. The Prince and Poins laugh uproariously at the success of their joke.
The robbery is a parody of the events in the main plot. Just as Falstaff and his crowd rob and are robbed in return, so Henry IV "robbed" King Richard of his crown and now may be robbed in turn by the rebels. The effect of mirroring the events of the main plot in the subplot is to undermine the high motives and ideals expressed by the nobles. They may dress up their motives in dignified language, but the stakes are the same: the desire for personal power and enrichment.