In this scene, we are introduced to a number of characters who are important to the plot of the play. The most important of these characters, however, is none other than Cassius, the son of King Henry IV. He has just woken up from a long night of sleep, and he is about to tell his friends that he is going to kill one of them, but he is interrupted by the sound of a crack in the wall. The crack is a warning that something is wrong with the plot.