Jessica's wanderings lead her to a locked oval-shaped door. Before she opens it, Mapes arrives to tell her that the Duke's men have come for Paul. Jessica tells the woman where to find her sleeping son. So, now we're caught up on that end of the story.
Jessica opens the palm lock using—what else?—Bene Gesserit powers.
Inside, Jessica finds an air-locked room serving as a conservatory. It even has yellow filter glass to create plant-friendly sunlight. The amount of water used to keep the room fresh must be substantial for a planet such as Arrakis.
Jessica also finds a letter from Margot Lady Fenring—Lord Fenring being the Emperor's proxy on Arrakis before the Atreides arrived. The letter warns that "the proximity of a desirable thing tempts one to overindulgences" and that "[o]n that path lies danger" (10.39).
Jessica searches for a hidden message and discovers one on a leaf positioned near the letter, written in super-top-secret Bene Gesserit code.
The message warns Jessica of the Baron's plans, including the attempt on Paul's life and the betrayal of a trusted friend. Naturally, the letter doesn't contain all the details—wouldn't want to spoil the surprise.
Paul enters the conservatory still clutching the hunter-seeker. Jessica orders him to throw it in some water to finish it off for good. Done, and done.
Jessica wonders if the betrayal of a friend suggests that Hawat will betray House Atreides, since he's the one who secured Paul's room. She shakes off the notion.
One of Hawat's men enters. He explains that they found the operator, but the man died before he could spill the beans on the whole betrayal thing. Isn't that always the way of those tricky assassins?
Since they believe the conservatory to be safe, Jessica and Paul stay inside while a guard takes position outside.
Jessica and Paul discuss Hawat and the letter. Jessica doesn't believe Hawat guilty of anything except being old and overworked, and she warns that the letter may exist simply to sow distrust amongst them. She tells Paul to tell his father, but only in private.
Jessica notices someone signaling through the conservatory window. It is in no code she has ever learned. It could only signify Harkonnens.
The chapter ends with Paul on his way to meet his father.