Glendower hosts Mortimer, Hotspur, and Worcester at his castle in Wales, where the rebels gather to strategize. Before we know it, Hotspur and Glendower start talking smack. Trash talk, as we know, is an Olympic sport in this play.
Hotspur swears and says he can't find his map but Glendower finds it and tells the young Percy to chill. Then Glendower tells Hotspur that King Henry wishes he were dead. Hotspur replies by saying that Henry wishes Glendower was in hell.
Glendower claims that Henry is afraid of him because, when he was born, the earth shook and the night sky was lit up by comets and lights.
Hotspur scoffs and says the same thing would have happened if Glendower's mother's cat had had a litter of kittens instead of Glendower being born.
When Glendower insists again that the heavens were on fire and the earth shook at his "nativity," Hotspur says the earth shook alright, but not because it was afraid of Glendower's birth. At the exact moment Glendower was born, says Hotspur, the earth let out a huge fart.
Mortimer tells Hotspur to knock it off and Glendower blows off Hotspur's insult – the Welshman insists that all kinds of strange things happened in nature at the moment of his birth.
He claims to be able to summons spirits from the ocean and says he can teach Hotspur how to command the devil, which is why he, Glendower, has been able to withstand King Henry's armies three times.
Hotspur says Glendower is full of it before the men look at a map of Britain and decide how they'll divide it into three territories.
Mortimer explains the rebels' plan of attack: tomorrow, he, Worcester, and Hotspur will ride to meet Northumberland and the Scotch rebels at Shrewsbury. He says his father-in-law, Glendower, won't join them just yet because he's still getting his forces together.
Glendower promises to meet up with them shortly and says he'll escort their wives too, since the women will be upset when their husbands leave to fight.
Hotspur, who has been looking at the map and thinking about the plans to divide the land, complains that his slice of the pie isn't as good as Glendower's. Bickering ensues.
Check out this map depicting how the rebels planned to divide the kingdom into three parts.
Hotspur bags on Glendower by insulting the sound of the Welsh language.
When Mortimer yells at Hotspur for being a jerk to his father-in-law, Hotspur complains that the old man talks too much – like a "tired horse, a railing wife."
Mortimer warns Hotspur that Glendower tolerates his rudeness only because he respects him. Worcester chimes in and tells the young Percy that his "pride" and "haughtiness" are ugly traits – he's going to lose the allegiance of his colleagues if he keeps it up.
Glendower trots out Lady Percy and Lady Mortimer so they can say goodbye to their husbands.
Mortimer says he's bummed because his wife can't speak English and he can't speak Welsh.
Glendower says his daughter doesn't want Mortimer to leave – she wants to go to war with him.
Note: Lady Mortimer doesn't get any lines of dialogue. Instead, the text gives stage directions like "The Lady speaks in Welsh" and then her father translates for her.
Mortimer says he understands her "kisses" and vows to learn Welsh so he can speak with his wife, who makes the language sound as sweet as music.
Mortimer lays his head in his wife's lap while she sings (accompanied by musicians).
The competitive Hotspur orders Kate to sit so he can put his head in her lap too.
Hotspur says the devil speaks Welsh and he'd rather hear his dog howl in Irish than listen to Lady Mortimer's singing.
Kate threatens to break Hotspur's "head" and Hotspur makes a naughty joke about sleeping with Mortimer's wife.
Hotspur then insists that Kate sing a song, too. When Kate refuses, he insults her by making fun of the way she talks – he says she talks more like a low-class woman than a lady.
Glendower and the wives stay behind while everyone else departs for Shrewsbury.