Artificial intelligence has long been outlawed. In its place, people use the drug melange, commonly known as spice, to perfect their mental capabilities. Spice is the most valuable resource in the universe, as it allows an expansion of the mind and even precognition.
The space guild, which has a monopoly on space travel and trade, uses spice to predict the future and safely plot courses through the universe. Spice is also used in Bene Gesserit rituals.
The Bene Gesserit is a matriarchal society that manipulates the galaxy in the shadows. The extensive training of their minds has allowed them to become hyper-observant, allowing them to perform tasks such as becoming teachers and human lie detectors.
Their true purpose, however, is to breed a superhuman individual known as the Kwisatz Haderach. They have selectively bred people for centuries to produce a man whose perception could transcend time and space.
Padishah Emperor Shaddam Corrino IV has begun to view House Atreides, led by Duke Leto, as a threat. The duke is gaining the respect of the other noble houses and training a fighting force that rivals the emperor’s own Sardaukar, his elite guard. The emperor works with Baron Vladimir Harkonnen to eliminate House Atreides and prevent Leto from challenging the throne.
The emperor commands Leto to take charge of Arrakis, a desert planet also known as Dune. Arrakis is the sole source of spice. Leto senses a trap, but accepts the commission to not directly disobey the emperor and take advantage of controlling spice mining.
As House Atreides prepares to leave the home planet of Caladan, the Reverend Mother Gaius Helen Mohaim, the Emperor’s Bene Gesserit truthsayer, visits Leto’s 15-year-old son, Paul. She performs a test on Paul that causes excruciating pain. She wishes to see if he does not panic or if he is ruled by emotion rather than reason. He passes the test.
The Bene Gesserit human breeding program should be one generation away from producing the Kwisatz Haderach, the ultimate human. The Kwisatz Haderach has the power to see through time and space. He is a man who can survive the Water of Life, a drug taken by Truthsayer Bene Gesserits to be able to see the past through the eyes of their ancestors.
Only women have been able to take the drug and survive. Jessica, Paul’s Bene Gesserit mother and the duke’s concubine, was commanded to birth a girl who would marry a Harkonnen and produce the Kwisatz Haderach. However, she produced Paul instead to please the duke and derailed the breeding program. The Reverend Mother was angered by this, but is impressed by Paul nonetheless. Paul has been trained by his mother in Bene Gesserit ways and has the capacity to see the future.
The Atreides arrive on Arrakis. Water is extremely rare on this desert planet. Fremen, a nomadic people that excel at surviving on the dangerous planet, inhabit it. They wear stillsuits, full-body outfits that recycle waste and expend very little water.
Bene Gesserit missionaries that arrived on the planet years ago implanted ideas in the Fremen’s minds. Because of this influence, the Fremen long for a savior who will convert Arrakis’ desert into a paradise. Leto notices their survival skills and aptness for fighting. He hopes to recruit and utilize them to counter attacks from the Harkonnens. Even when they first arrive, the Fremen suspect that Paul may the messiah of legend.
Spice mining is extremely dangerous. The worms, or makers, of Dune are huge, capable of swallowing an entire mining vessel. The worms have a symbiotic relationship with the spice. Every time spice is mined, the worms attack. The duke and Paul oversee a mining expedition under the supervision of Arrakis’ planetologist, Liet Kynes, a man who lives among the Fremen and attempts to better the planet’s harsh climate. The duke rescues his workers when a worm attacks.
The Harkonnens ensure that the Atreides discover false information that implies that Jessica is a traitor and will have a leading role in killing the duke. The duke’s men, including Gurney Halleck and Thufir Hawat, suspect Jessica, but the duke is not convinced. Thufir Hawat is a mentat, an individual trained to make computer-like calculations. Thufir is also the head of Leto’s assassins, who protect the duke.
The Harkonnens get information from Dr. Yueh on Leto's staff, torturing his wife and forcing him to betray the duke in order to end her pain. House Harkonnen attacks and penetrates the Atreides’ offenses using Harkonnen soldiers and Sardaukar disguised as Harkonnen.
Yueh hates the Harkonnens deeply, so he helps Jessica and Paul escape. He also implants a tooth in Leto’s mouth that will release a poison gas when he bites down so he can kill the baron. The baron kills Yueh. Leto bites down on his poison tooth and dies, but the poison gas kills the baron’s mentat Piter instead of the baron himself.
Most of Leto’s men are killed, but Gurney Halleck and Thufir Hawat survive. They both believe Jessica is responsible for the duke’s death. Gurney becomes a smuggler on Arrakis to take revenge against the Harkonnens, and Thufir is manipulated to become the baron’s mentat. However, the baron gives Thufir a poison. If Thufir tries to abandon the Harkonnens, he will no longer receive the antidote and die.
After Leto’s death, Paul’s precognitive abilities increase. He realizes Jessica is the baron’s illegitimate daughter. He must find the Fremen and use his power to enlist their service. However, he fears a jihad, or that the Fremen’s religious devotion to Paul will cause them to go on a violent spree throughout the universe. Kynes and Duncan Idaho, Leto’s men, meet up with Paul and Jessica. Kynes promises to utilize the Fremen and help Paul, but the Harkonnens attack and kill Kynes and Duncan. Jessica and Paul fly into a dangerous storm. They are assumed dead.
Paul and Jessica cross the desert of Arrakis and find the Fremen. The Fremen attack Paul and Jessica, intending to kill them and take their water, but they fight back with Bene Gesserit techniques. They prove their worth, and the Fremen allow the two to live with them. However, a Fremen that Paul bested, Jamis, challenges Paul to one-on-one combat.
Paul accepts and hesitates to kill Jamis, but eventually does so reluctantly. At Jamis’ funeral, Paul sheds tears for Jamis, which the Fremen consider to be the greatest honor one can give the dead. Paul takes the Fremen name Muad’Dib.
The Fremen, along with Paul and Jessica, reach their hidden settlement. The tribe’s Reverend Mother is on the verge of death, so they decide to let Jessica, a Bene Gesserit, become the Reverend Mother. Jessica drinks of a drug, before she realizes it's the Water of Life, a drug that allows a woman to gain the memories of her female ancestors.
Jessica is pregnant with Leto’s daughter, so the unborn child receives this wisdom before she is born. Jessica becomes the Reverend Mother of the tribe. Paul’s precognitive abilities expand further due to the Fremen’s spice diet. Paul and Jessica teach the Fremen Bene Gesserit techniques to improve their fighting abilities.
Two years later, Paul has taken a Fremen woman, Chani, as a lover, and they have had a son, Leto II. Paul has begun to lead the Fremen people using his future sight, becoming a religious figure to them. The Fremen believe Paul is the messiah of legend.
Jessica has given birth to a girl, Alia. Due to receiving the Water of Life in the womb, Alia has knowledge that she should not have at her age. She acts wise beyond her years and makes the Fremen uncomfortable.
Paul rides a worm, which is regarded as his Fremen passage to manhood. Paul is expected to kill Stilgar, the leader of his tribe, and take up the mantle of leadership. Instead, Paul declares himself Duke of Atreides, as his father was, and leaves Stilgar in command.
A smuggling vessel overextends, attempting to mine spice in Fremen territory. Paul leads a group of Fremen to attack the smugglers. He is reunited with Gurney Halleck. Gurney is shocked and elated that Paul is alive, and volunteers his service. Some of his men turn out to be the Sardaukar in disguise, and they kill some of the Fremen. However, Paul allows them to escape and report to the emperor that Paul is alive.
Paul begins to prepare for a great battle, intending to reclaim Arrakis. Gurney tries to kill Jessica, still believing that she is responsible for Leto’s death. Paul tells him that she was not the traitor and explains Yueh's treachery. Gurney is distraught and tells Paul to kill him, but Jessica and Paul forgive him.
Paul did not predict Gurney’s attack, so Paul is reminded that his powers of prescience are limited. He takes a tiny portion of the Water of Life, a drug that has killed all men who have taken it. He spends three weeks in a coma, but wakes with greater prescient skills.
He fulfills the Bene Gesserits’ prophecy of the Kwisatz Haderach. Paul sees the armies of the emperor and Harkonnens approaching Arrakis to quell the Fremen rebellion. Paul also discovers that he can destroy all the spice on Arrakis if he wants to.
As Paul and his army prepare to attack the capital of Dune, the emperor's forces capture Alia and kill Paul's son. Alia meets the emperor, the baron and the Reverend Mother Gaius Helen Mohaim. Alia disturbs the Reverend Mother, and she calls Alia an abomination. After using his family’s atomic weapons to destroy the shield wall around the capital, Paul and the Fremen attack, riding on sand worms. Alia kills the baron in the confusion.
Paul is victorious and retakes Arrakis, but he is deeply shaken by the death of his son. He meets to discuss terms with the emperor, threatening to destroy the spice to force the emperor to accept his demands. Harkonnen Feyd-Rautha, the heir to the baron, challenges Paul to a fight, and he accepts.
Even though Feyd-Rautha attacks with poison weapons, Paul defeats Feyd-Rautha. The emperor abdicates the throne, retreating to his prison planet Salusa Secundus with most of his family and close supporters. However, Irulan, the emperor’s eldest daughter, stays on Arrakis to marry Paul.
Chani, Paul’s Fremen lover, remains as Paul’s concubine, receiving Paul’s affection and siring his heirs. Irulan will be Paul’s wife in name only, resigning herself to be satisfied by writing about his life. Paul promises the Fremen that Arrakis will be a garden planet, but the deserts will remain so the worms and spice can survive.