At Windsor Castle, Richard II just wants to chill out and enjoy the benefits of being a king who (almost) everyone thinks has been handpicked by God to rule England. But he can't relax because two seriously angry noblemen have arrived at the castle and want him to play Judge Judy.
The angry noblemen are Henry Bolingbroke and Mowbray. Richard invites them in and asks what the problem is.
Bolingbroke and Mowbray are pretty formal here – they bow down to the king and proceed to do a lot of brown-nosing.
Richard's not having it. He orders each one to give his side.
Things heat up pretty quickly. Bolingbroke and Mowbray immediately start to hurl a lot of nasty accusations and creative insults at each other, which sound a lot like this:
Bolingbroke: I'm officially accusing you of being a traitor, Mowbray! And if I could, I'd stuff my words down your throat.
Mowbray: You talk a lot of trash, Bolingbroke. And by the way, talking trash is for girls who fight with words because they can't fight with swords, which is why I'm not going to do it. But, if I were going to talk smack, I'd say that you're a "slanderous coward and a villain."
Bolingbroke: Don't worry, Mowbray – I'll put my money where my mouth is. In fact, I'm going to get medieval on you with my sword.
In the middle of all this trash talk, Bolingbroke throws down his "gage" (probably a glove or a hat), an official challenge to throwdown.
Mowbray reaches down and picks up the gage. Challenge accepted.
Finally we find out what all the fuss is about. Bolingbroke accuses Mowbray of stealing a bunch of money from the crown and plotting against the kingdom.
Then Bolingbroke gets to the good stuff: he accuses Mowbray of killing Richard's uncle, Thomas of Woodstock, the Duke of Gloucester (who is Bolingbroke's uncle, too).
Mowbray is pretty adamant that he's not a thief or a traitor, but he waffles when it comes to whether or not he's responsible for Gloucester's death. (Don't worry – we find out more in the next scene.)
Mowbray doesn't want to look like a wimp, so he throws down his gage.
Naturally, Bolingbroke picks it up.
King Richard tries to make peace, but it's no use. Bolingbroke says he'll never agree to a truce. In fact, he'd rather tear out his own tongue with his teeth and spit it in Mowbray's face. (Gross.)
Richard is exasperated by all this gage throwing and threat-making. He gets all huffy and says he doesn't have time to play Dr. Phil. They can have their fight – a trial by combat at Coventry.
Brain Snack: A trial by combat is when two guys (usually knights) duke it out in a crowded tournament arena until one or the other dies or can't get up – sort of like going into a Mixed Martial Arts Octagon, except with swords and stuff. These trials were common in medieval England (the setting here) but they were pretty old-school and outdated by the time Shakespeare was writing the play. (And yes, the trial by combat is the great grandfather of the "wild west gunfight," where two cowboys take twenty paces before drawing their weapons from their holsters and blasting each other.)