- Alia Atreides is possessed by the dead Baron Vladmir Harkonnen.
- Jessica and Gurney Halleck return to Arrakis.
- Leto and Ghanima realize that the terraforming of Arrakis will kill all the sandworms, thus destroying the source of the spice.
- Paul Atreides, as The Preacher, begins railing against the religious government's injustices and the changes among the Fremen. He journeys to Salusa Secundus to meet Wensicia Corrino's son Farad'n, and in return pledges Duncan Idaho as an agent of House Corrino.
- Alia attempts to assassinate Jessica, who escapes into the desert with Duncan's help, precipitating a rebellion among the Fremen.
- Leto seeks out The Preacher. Everyone else thinks he is dead. He finds him and discovers he is Paul, killing his guide Assan Tariq.
- Duncan and Jessica flee to Salusa Secundus, where Jessica begins to mentor Farad'n, who seizes power from his mother and allies with the Bene Gesserit. Jessica orders Gurney Halleck to infiltrate a group of Fremen outlaws who capture Leto. On Gurney's suggestion, they force him to undergo the spice trance. Leto escapes and sacrifices his humanity in pursuit of the Golden Path by physically fusing with a school of sandtrout. He travels across the desert and confronts his father.
- Stilgar kills the ghola Duncan Idaho, after he kills Javid and provokes Stilgar.
- Stilgar kills Buer Argaves.
- Paul and Leto return to the capital to confront Alia. Upon arriving, Paul is murdered. Alia manages to commit suicide by throwing herself off a high balcony.
- Leto ascends the imperial throne as Leto II, and sets humanity on the Golden Path, his vision of the future. He takes the Bene Gesserit breeding program into his own hands by interbreeding the genes of Farad’n Corrino and Ghanima Atreides. His control over the spice forces peace and calmness on humanity.
- Leto orders a new Duncan Idaho ghola from the Tleilaxu to serve him as Swordmaster and leader of the Fish Speakers, the all-female army he begins assembling. He will continue to purchase new Duncans to serve him over the next 3,500 years.
- Farad'n gives Leto the Sardaukar.