At his castle in Northumberland, Hotspur reads to himself a letter from an unidentified person. The writer is refusing to join the rebellion against the King. He says the enterprise is too dangerous, the forces not reliable, and the time not right. Hotspur is angry at the refusal. Speaking out loud to himself (and for the benefit of the audience), he says that the forces have been raised and will be ready to join up with him on the ninth day of the following month. Hotspur fears that the writer of the letter will betray their plot to the King. But then he says he does not care if the man does. The rebels are well prepared enough.
His wife enters. She is unhappy because Hotspur has been neglecting her, staying up all night and brooding alone. When he does sleep, he mutters to himself about battles. She wants to know what is going on.
Before Hotspur can react, a servant enters and informs him that a man has arrived with a horse for him. Hotspur greets this news enthusiastically. When his wife asks him again what is wrong, and why he is going away, Hotspur at first tries to laugh the question off. But his wife persists. She has already guessed that Hotspur is off on a military expedition connected with her brother Mortimer. But he remains evasive when she tries to question him further. He says he does not love her, and it is time for war, not love. She asks him whether he is joking. Hotspur still refuses to give her a direct answer, and tells her she must not ask him where he is going. He says he goes where he must go, and that is all there is to it. He must leave that very night. He cannot trust her to keep a secret, so he is not going to tell her anything. But then he seems to relent and says that wherever he goes, she shall go too, but she will travel a day behind him. His wife reluctantly accepts this, since she has no other option.
This scene allows us to see Hotspur in more detail. He is the only character granted an entire scene in which to reveal his character. As he discounts the fears expressed in the letter he reads, he once again shows he has the fearless courage, but also the recklessness, of youth. He refuses to take warnings seriously, or even give them a hearing. The words of his wife about his muttering in his sleep show how eager for battle he is. But Hotspur is also a likeable character. He has a warmth the others lack. His playful dialogue with his wife, and the affectionate terms she uses when she talks to him, show him in a very human light. He may be impetuous and probably immature, but he wins our sympathy.