Shakespeare uses juxtaposition(placing the two plots for comparison), antithesis(contrast), and inversion (interchanging of position)to compare Henry IV's court that is plagued by problems and the light-hearted silly shenanigans of the tavern that Sir John Falstaff leads. He also condenses the true historical events time-line for dramatic purposes.
In act one scene one the exposition and the opening scene begins with king henry iv saying "so shaken as we are so wan with care". this explains what had happen before the play began and possibly what is to happen.He talks of going on a crusade to the holy land jeruselem, and later on in the scene he immediately puts hotspur as his son hal the protogonist foil, and hotspur is believed to be the very personification of honour. there is news that mortimer had been captured by the welsh hence we are left to wonder what will happen to him and hotspur had also capture some of king henry's soldier. also we see that the percy family help to bring him to power and he has abondon them. hence what will happen.