Dune - 1984
While the Atreides had anticipated a trap, they are unable to withstand the Harkonnen attack, which is aided by the Emperor's elite troops, the Sardaukar, and by a traitor within House Atreides itself, Dr. Wellington Yueh (Dean Stockwell). Yueh plans revenge on Baron Harkonnen for the death of his wife. Captured, Leto dies in a failed attempt to assassinate the baron using a poison gas capsule planted in his tooth by Dr. Yueh; with his vision fogged by drugs, Leto kills the baron's aide Piter De Vries (Brad Dourif) instead.
With Piter dead, Captain Iakin Nefud (Jack Nance), the baron's head of security, takes over Piter's duties as the baron's valet and aide. Dr. Kynes is captured and killed by the baron himself. Thufir is forced to take over as director of spice mining for the Harkonnens, while Rabban becomes de facto governor of Arrakis. Paul and Jessica, who is pregnant by Duke Leto, escape into the deep desert, where they manage to join a band of Fremen led by Stilgar (Everett McGill).
Paul adopts the title of Muad'Dib, and the Fremen suspect he is the leader they have been waiting for. Paul teaches the Fremen (who are formidable warriors) how to fight using the weirding modules and begins targeting mining production of spice to stop its flow. Stilgar trains Paul in Fremen traditions, and Paul rides his first sandworm. The Fremen's Bene Gesserit reverend mother has aged and Jessica drinks the Water of Life to replace her.
The poisonous water causes her to go into convulsions and premature labor, her eyes bleed, and the transmutation of the sacred water awakens her knowledge. Jessica's daughter Alia (Alicia Witt) is born prematurely, but has blue-tinted eyes because of the spice and the knowledge imparted by the Water of Life. Within two years she grows rapidly into a young girl with great powers.
During the war against the Spacing Guild, the Fremen, with Paul as their leader, effectively halt spice production on Arrakis. The Guild warns the emperor that he must intervene; they fear Paul will take the Water of Life. During a skirmish, Paul meets his former mentor Gurney Halleck, now a smuggler, who surrenders and immediately joins Paul and the Fremen to continue the war and maintain the strangle-hold on spice production.
Paul begins a romance with Chani (Sean Young), the daughter of the leader Dr. Kynes (known to the Fremen as Liet). After a vision, Paul can no longer see his future and decides to drink the Water of Life. Paul goes into the desert with Chani and a cadre of bodyguards, drinks the Water of Life, and enters a coma-like state. Awakening literally and figuratively, he is transformed and gains control of the sandworms of Arrakis and the secret of the spice.
He has discovered that water kept hidden in huge caches by the Fremen can be used to destroy the spice. Paul has also seen into space and the future; the emperor is amassing a huge invasion fleet above Arrakis to regain control of the planet and the spice. When the emperor arrives on Arrakis, he executes the incompetent Rabban for failing to remedy the spice situation.
Alia is brought in as a hostage, and she delivers a message: Paul is coming for them. Paul launches a final attack against the Harkonnens and the emperor at the capital city of Arrakeen, riding in with the Fremen on sandworms. After a climactic and fierce battle, where casualties are heavy on both sides, Paul and the Fremen warriors defeat the emperor's legions of Sardaukar, while Paul's sister Alia sends Baron Harkonnen into the jaws of a sandworm.
Afterward, Paul, Stilgar, Gurney, Alia, Jessica, and their army confront the captive emperor, Princess Irulan, and their staff. Paul is challenged to a duel with daggers by the psychotic Feyd. After a short but brutal fight, Paul stabs Feyd in the neck and uses his vocal powers to explode his internal organs, killing him.
Paul faces the defeated emperor, relieves him of power, and announces an era of peace for all of humanity. Storm clouds gather and it begins raining on Arrakis for the first time in the planet's existence. Alia declares, "And how can this be? For he is the Kwisatz Haderach!"