Jessica notices the gathering of the tribes, all clamoring for Paul to kill Stilgar and lead them to victory. Jessica thinks about how they must not lose Stilgar.
Meanwhile, Paul's mind is on a message stolen from a Harkonnen courier. Rabban has been abandoned by his uncle. The time to strike is now.
Paul addresses the crowd. First off, he's not going to kill Stilgar, so don't even ask.
Then Paul puts on his father's signet ring, proclaiming himself the Duke of Arrakis. He has Stilgar give him his crysknife. Paul performs a knighting ceremony, because dukes can do that kind of thing.
The crowd loves it. Paul will lead; Stilgar doesn't have to die or lose face as tribal leader; and they are going to kill Harkonnens. Win. Win. Win.
Paul brings his mother to an inner chamber and tells her to wait. He's got a surprise for her.
It's Gurney, Mom: the man who thinks you're a traitor and wants to see you dead. Surprise.
Gurney gets behind Jessica and has his knife poised near her spine lickety-split.
Paul enters. He tries to convince Gurney that Yueh was the traitor, but the Imperial Conditioning face prevents Gurney from seeing the truth. Paul reminds Gurney that the man has not heard his mother crying in the night. Oh, and there is also the letter written by Yueh admitting the treachery.
Gurney realizes the error of his ways.
Gurney begs Paul or Jessica to kill him for his betrayal, but they're like, "Dude, it's embarrassing enough without this. Stop it all ready." (We, of course, have paraphrased their actual dialogue.)
Jessica, Paul, and Gurney sit and have the talk they were meant to have before the whole "I'm going to kill you" incident.
Paul excuses himself while Gurney plays the baliset for his Lady.
Outside the room, Paul comes to a decision. He will find out if he truly is the Kwisatz Haderach by taking the test of the Reverend Mothers.