Meanwhile, at Warkworth Castle in Northumberland, Hotspur reads a letter from someone who refuses to take part in the rebellion because it's too dangerous and the parties involved are untrustworthy. (Note: the play never reveals who wrote the letter.)
Hotspur, ticked off about the letter, rants and raves to himself before his wife, Kate, enters the room.
Hotspur announces he's leaving in two hours and Lady Percy complains about being neglected by her husband. He hasn't been fulfilling his duties in bed. She asks what's bothering him and wants to know why he thrashes around and talks in his sleep about combat.
Kate says if Hotspur doesn't tell her what's up, then it means he doesn't love her.
Hotspur ignores Kate and talks to his servant about his horse. (We guess he doesn't love her.)
Kate asks again why Percy's leaving and says she suspects her brother, Mortimer, is somehow involved. Kate and Hotspur banter back and forth a bit. Kate is witty and indulgent and Hotspur's kind of a jerk. He claims not to love his wife and says now's not the time for hanky-panky – he's planning a bloody rebellion here.
Hotspur says he's leaving soon and he can't tell Kate what's going on because she's a woman, which means she can't keep a secret. But, he promises that Kate will follow him tomorrow.