Several ships land behind Arrakis’s rocky shield wall. The emperor has come to Arrakis, along with Baron Harkonnen and five legions of Sardaukar. Stilgar and Paul’s plan is to wait until a great sandstorm strikes, and then break the shield wall with atomic weapons. Next, the Fremen will blast the noses off the spaceships so that the vehicles cannot take off. Then the Fremen will rush the Sardaukar, while the people of Arrakis rise up against the emperor and his forces.

When the sandstorm hits, Halleck blows up the shield wall. As Paul and his soldiers prepare for battle with the Sardaukar, they receive a message from Sietch Tabr: it has been raided, and many of its inhabitants have been killed, including Paul’s son, Leto. Alia has been captured. Chani and Jessica were hiding out closer to the city, so they were not at Sietch Tabr during the raid.

Meanwhile, inside the emperor’s ship, just before the shield is attacked, the baron and the emperor discuss their plans. Feyd-Rautha and Rabban are also members of the party, though they are outside the ship, scouting the perimeter. The emperor presents Alia, whom his men have captured, to the group. The emperor is enraged since only a handful of his Sardaukar got away from old men, women, and children, as the Fremen are such excellent fighters.

The emperor’s truthsayer, or one who detects sincerity, is the Reverend Mother Gaius Helen Mohiam. Mohiam calls Alia an abomination—Alia has the consciousness of all reverend mothers of the past; therefore, she knows all of Mohiam’s memories and is inside her mind. Just as the emperor is threatening Paul, the Fremen strike, destroying the shield wall. Alia kills the baron—who is her grandfather—with her gom jabbar and escapes. The emperor hears reports that the Fremen have breached the shields of his ships and have broken the ships’ noses so they cannot lift off. Shocked, the emperor and his troops see the Fremen riding toward them on dozens of giant sandworms. The Fremen soon defeat the Sardaukar, and Paul resumes his place on the throne at the Arrakeen governor’s mansion. Paul sends a Sardaukar captive as a messenger to the emperor to discuss the terms of the emperor’s surrender. Paul, however, is worried: he still sees the jihad ahead of him. He now accepts the fact that he is the Kwisatz Haderach.

Chani and Jessica arrive, and then the emperor and his entourage appear. Paul asks Thufir Hawat to come forward. The baron secretly administered poisons to Hawat, and Hawat is near death. The emperor has given Hawat a poisonous needle to use to kill Paul, but Hawat refuses and dies in Paul’s arms.

The emperor threatens to command the House of Landsraad ships to attack the Fremen, but Paul orders the representatives of the Spacing Guild to force the House of Landsraad ships to leave. Paul threatens that if they do not leave, Paul will destroy all the spice on Arrakis, robbing the Guildsmen of their supply. The Guildsmen obey Paul’s orders, angering the emperor, who is powerless without the support of the Guild. Paul then turns his attention to the Reverend Mother Mohiam, telling her that he refuses to do the bidding of the Bene Gesserit or to be the cause of the jihad, which even the Bene Gesserit do not realize is their ultimate goal.

Feyd-Rautha challenges Paul to a duel, and Paul accepts despite his followers’ protests. Feyd-Rautha cheats, as always, but he still fails and Paul kills him. The emperor tries to get Count Fenring to kill Paul, and Paul realizes that Fenring was almost a Kwisatz Haderach himself. Fenring refuses to attack Paul, which enrages the emperor. Paul then asks for the throne through a marriage to Princess Irulan, the Emperor’s daughter. The emperor reluctantly agrees, and Chani negotiates the settlement. Paul assures her that while Princess Irulan will be the “royal concubine,” it is Chani who will be his true wife.

Just as Paul does not know how he intends to avert the jihad, we also do not know how he plans to bring peace and not war. Herbert offers only one allusion to Paul’s future plans, when Paul thinks, “They sense that I must take the throne. . . . But they cannot know I do it to prevent the jihad.” As the new emperor, the most powerful person in the universe, Paul hopes to prevent the bloody deaths of millions. The idea of saving lives casts a new light on the quotations by Princess Irulan that we have read throughout the book. We do not know whether these quotations are in praise of a great religious leader who brought a time of peace or in praise of a person who has brought war. Historically, the peaceful messianic figures are remembered better than the wrathful ones. However, we still do not know whether the Fremen will become soldiers of war or guardians of peace.

Dune’s final pages are filled with fast-moving action that ends abruptly. The final battle and Paul’s successes are anticlimactic; we do not feel satisfied with the novel’s conclusion. Without even an epilogue, it appears that Herbert intended a sequel to Dune, and there are eventually five sequels. The last few parts of the novel seem rushed and unfinished. The minds of Paul, Jessica, and the Reverend Mother Mohiam are filled with weighty thoughts, but none of these is resolved or explored any further, as the characters just want Paul to be enthroned as the new emperor as quickly as possible.

Paul’s ascension to the emperorship and the Fremen’s regaining of control complete the reversal of status that occurs during the course of the novel. At the beginning of the novel, the emperor and the Harkonnen dominated the Atreides and the Fremen. The power structure of Dune has changed since Paul was on Caladan. Duke Leto is dead and now Paul is not only duke of Arrakis, but also the new emperor of the universe. The Fremen have regained control of their world and will soon turn it into the garden paradise they have long desired. Once this change occurs, however, we wonder how the Fremen’s culture will change—whether they will retire into easy lives of spice mining or follow their prophet into space.

Dune is still widely read and considered a landmark of science-fiction writing because it combines fantasy and science fiction with important social issues about the environment, religion, human social interaction, and genetic development. Dune was ahead of its time in pointing out the importance of ecological preservation and conservation of resources. Also, by addressing religion’s complexity, Dune explored a topic that was rarely addressed by science fiction prior to the novel’s publication. Today, the issues that Dune addresses are perhaps more relevant than they were forty years ago.