The epigraph from Princess Irulan’s text “Songs of Muad’Dib” recounts “The Dirge for Jamis on the Funeral Plain.” It is a mournful elegy that recounts a foolish and restless waste of a life.
It does not make any sense to readers yet, but the narrator uses Princess Irulan’s epigraph to foreshadow Paul’s future victory in a lethal duel with a Fremen named Jamis. The accurate record of Irulan’s future texts serves to add a legitimacy to the theme of Dune’s predeterminism.
Duke Leto stands in the palace foyer, considering a strange note from a Fremen messenger that reads “A column of smoke by day, a pillar of fire by night.” The messenger cannot be found to explain the mysterious note. Leto feels very weary. He reflects on his recent meeting with Thufir Hawat, where the Mentat related his conversation with Lady Jessica to the Duke. After blaming the drunken Duncan Idaho for starting the unfortunate chain of events, Leto realizes that he should have been honest with Jessica from the beginning regarding his pretense of suspicion.
It is too late for Duke Leto to undo the mistakes he has recently made on his move to Arrakis—the Harkonnen attack and his death are imminent. He is also unable to decipher the Fremen hint that the Harkonnens will attack tonight.
Leto hurries to waken Jessica and make amends, but walking down a hallway hears a strange mewling noise. Tracking it, he discovers the smuggler Tuek stabbed to death on the floor. The Atreides housekeeper Shadout Mapes has been stabbed also and is taking her last breaths as she tries to tell Leto who the traitor is. She dies, and Leto is struck in the arm by a poisoned dart.
Even in the midst of violent injury and death, Duke Leto fails to realize the danger until it is too late and he is incapacitated.
As his body is overcome by paralysis, Duke Leto turns over and sees that Dr. Yueh is the traitor. Yueh has turned off the house generators, leaving the Atreides household unprotected from a Harkonnen attack. Yueh reveals that he has betrayed the Duke so that he can kill the Baron Harkonnen, taking vengeance for House Harkonnen kidnapping and likely murdering his wife. The Suk doctor places a false tooth filled with poisonous gas in Leto’s mouth, instructing the Duke that he must bite down hard when he is brought before the Baron.
The fragile Atreides rule on Arrakis has come to an end as Yueh’s betrayal leaves them vulnerable to Harkonnen and Imperial forces. Yueh was a member of a household that the Duke never considered as capable of betrayal because of the Suk Imperial Conditioning. The much-trusted Mentat Hawat failed in his recognition of this threat, too.
Yueh feels a great relief in executing his revenge on House Harkonnen, but is also extremely guilty over his betraying House Atreides. He tells Duke Leto that if the Duke will kill Baron Harkonnen, Yueh will ensure that Paul and Jessica escape the Harkonnen attack—he will make them appear dead and then hide them with enemies of House Harkonnen. As Leto blacks out, he feels Yueh remove his ducal ring and hears the doctor reminding him of the secret false tooth.
As he has in the lead up to his betrayal of House Atreides, Yueh feels great remorse at having harmed the Duke. He tries to allow the Duke two reassurances to ensure his impending death is a little more bearable.