At Warkworth castle, Northumberland, Lady Northumberland, and Lady Percy are discussing Northumberland’s plans to join forces with the rebellion. Against his wife’s protests, he cites his need to uphold his word and honor. Lady Percy acidly points out that he didn’t seem to care about breaking his word to his own son when he failed to deliver the supporting troops he’d promised to Hotspur at Shrewsbury. If it weren’t for Northumberland’s broken promise, Lady Percy points out, Hotspur would still be alive and she wouldn’t be widowed. Northumberland is ashamed. Lady Northumberland suggests he run away to Scotland for now and can come back to assist the rebels once they’re more organized. Northumberland reluctantly agrees.
Northumberland’s discussion with his widowed daughter-in-law Lady Percy (who was the wife of Hotspur) connects the themes of Lies and Warfare, revealing that Northumberland’s cowardly lying (to avoid involving himself in the Battle of Shrewsbury) resulted in grave military and personal consequences: the battle was lost and his son was killed. Yet Lady Percy’s criticisms aren’t enough to persuade Northumberland to join the rebels this time, as his wife’s advice to protect himself by running away (along with the face-saving lie that he can always return) is what Northumberland agrees to.