In act two, we hear about Hotspur’s plans—which seem to be far more complex than they need to be really—to dethrone King Henry the fourth, which include getting the Scottish help and the like. In the beginning of Act three these conspirators which includes Mortimer and Glyndwr among its midst, meet to begin their actual planning. Glyndwr is one of the Scottish and Mortimer’s father in law, who appears to have agreed to help him. Glyndwr reveals that he has sent back and beaten the army that Henry has sent against him a total of three times before, which makes him a good ally for them to have to over throw Henry.
At any rate, to say that Glyndwr and Hotspur do not get along upon first meeting would be one heck of an understatement. It begins with them seeming to attempt to flatter each other by saying that King Henry both wishes them dead, however, when Glyndwr mentions that the earth shook when he was born, among other cosmic events such as the shooting stars and the heavens being on fire, it seems to cause a bit of that old game “my horse is bigger than your horse” to occur. Glyndwr offers up more events that occurred on the day of his birth, and each time Hotspur denies the truth of these events or offers up other reasons for these events occurring. “O, then the earth shook to see the heavens on fire,/ And not in fear of your nativity” (3.1.23-24). He also insults Glyndwr to say that the other man speaks the best Welsh, implying that he is a barbarian and that he speaks in nonsense. Despite the fact that Mortimer tries to stop this boasting match, both men seem to ignore the warnings and will not take peace.
Hotspur implies that Glyndwr is crazy, and that he can do something that everyone can do and seem crazy when he says that anyone can attempt to call spirits but that doesn’t mean they’ll call, which appears to be him calling the Scot ineffectual, and that he doesn’t need the help.
Though the men eventually do get themselves on track—with Hotspur and Glyndwr constantly clashing throughout—this first meeting could be seen as foreshadowing in a certain respect. If these two allies cannot keep themselves on track and keep from fighting each other when they are simply planning what they are to do next, how can they possibly hope to keep themselves on track when they are banding together to go against Henry? Hotspur certainly lives up to his name in this moment, being hot tempered and constantly lashing out, even after Glyndwr has left them to go get the ladies. Both other men blame Hotspur for his temper, which is something we do see time and time again how Shakespeare plays on the name that the character has.
Will Hotspur be the outdoing of his own plan? It seems so if his temper would keep going at the rate that it is. It was his temper that caused him to create this plan, and it could be his temper that causes him to break from his allies or make them angry in turn with him and have it fall apart.