When the scene opens, John of Gaunt is in the middle of a private chitchat with his sister-in-law, the Duchess of Gloucester. The Duchess is the widow of the late Thomas of Woodstock, Duke of Gloucester.
The Duchess is heartbroken about her husband's murder and has just asked her brother-in-law (John of Gaunt) to avenge his death.
Gaunt admits to the Duchess that her husband (his brother) was murdered. But he says she is out of luck if she expects him to do anything about it, because there's no way he's going to lift a finger against the king.
(The king? Say what?! Okay, Shmoopsters. Shakespeare's letting us in on the big secret here. It turns out that Mowbray was involved in the murder the king's Uncle Gloucester, but King Richard ordered him to do it. No wonder Mowbray acted all weird when Bolingbroke accused him of the murder.)
The Duchess accuses John of Gaunt of being a lousy brother. She argues that loyalty to one's own flesh and blood is the most important thing in the world.
Then she reminds him of his family history: he's one of King Edward III's sons. In other words, he's royal, and so was his brother, which is why Richard shouldn't be allowed to get away with murdering his uncle, even if Richard is a king.
Gaunt disagrees. He argues that he can't do anything to Richard because he's a monarch and, like all kings, he's God's "deputy" on earth.
Brain Snack: Gaunt's talking about a political theory that's often referred to as the "divine right of kings," which says that kings have a right to rule because they've been chosen by God to do so. What this means is that kings don't have to answer to anybody but God. This also means that if a subject rebels against the king, he's basically rebelling and sinning against God too. Now, back to the play.
Fine, says the Duchess, but where the heck is she supposed to go for justice if Gaunt's not going to help her get revenge?
Gaunt says she'll have to take it up with God – he's the only one who can help her.
The Duchess gives up the argument but adds that she hopes that Bolingbroke's sword will "butcher Mowbray's breast" at the big trial by combat that's coming up.
Then the Duchess hints that she's going to go off to die of grief and/or commit suicide.