More than twenty thousand years into the future, humankind is spread across the universe living in a feudal society with the Padishah Emperor at its head. The Emperor has recently given control of the desert planet Arrakis to House Atreides, one of the Imperium’s powerful Great Houses. Despite its hostile desert climate, Arrakis is a valuable holding, as it is the only planet that produces the profitable crop called spice (also known as melange). Spice is a highly addictive drug that can be ingested as a mind-altering substance to increase human lifespan, allow interstellar travel, and open the human mind to higher cognitive functions including prescience.
The novel opens with Duke Leto Atreides moving his son Paul, his concubine Lady Jessica, their noble household, and the Atreides military forces from his home planet Caladan to Arrakis. The Duke is popular as a fair and virtuous leader, although he has historic enemies in rival House Harkonnen. Lady Jessica is a member of the Bene Gesserit order, a matriarchal program who use cognitive abilities and genetic breeding to hold power in the wider universe. One of the Bene Gesserit leaders, Reverend Mother Gaius Helen Mohiam, visits Caladan and demands a meeting with fifteen-year-old Paul Atreides. Paul has impressive mental and physical abilities due to the training he has received from his mother and from renowned warriors Gurney Halleck and Duncan Idaho. The Reverend Mother puts Paul through a dangerous test whereby he must prove his humanity by overcoming instinctual reactions to fear and pain using cognitive rationality and control; if he fails the test, Paul will meet death through the gom jabbar (a poison-tipped needle that the Reverend Mother holds to his neck during the ordeal). Paul demonstrates courage and self-control to pass the test. He also learns that there is a chance that he is the Bene Gesserit’s promised Kwisatz Haderach, a male individual who will have higher cognitive awareness than all other humans, although the Reverend Mother dismisses this possibility.
Meanwhile, the greedy and corrupt Baron Vladimir Harkonnen plots against his cousin Duke Leto. The Baron and his Mentat Piter de Vries have managed to turn one of the Duke’s most trusted advisors, Dr. Wellington Yueh, to the Harkonnen cause. This is an impressive feat, as to do so they have subverted Yueh’s Suk Imperial Conditioning to do no harm to other humans. The betrayal is planned to take place on Arrakis, which was under Harkonnen control before the Emperor re-gifted its governance to the Atreides.
Shortly after the Reverend Mother’s visit, the Atreides leave water-rich Caladan for arid Arrakis. The planet is also known as “Dune” due to its vast and barren desert landscapes. It is home to tribes of Fremen, a hardy people who survive outside of Arrakis’s cities in the harsh wilderness environments. Duke Leto must balance the needs of Arrakis’s people with his suspicion that House Harkonnen will attack his household during the period of change. Leto’s trusted Mentat, Thurfir Hawat, wrongly suspects that Lady Jessica is a traitor, causing tension between Leto and Jessica.
When the Harkonnens attack with the support of Imperial Sardaukar troops disguised as Harkonnens, Leto is shocked to learn that it is Yueh who betrays House Atreides. Leto, Jessica, and Paul are captured, but Yueh contrives for Jessica and Paul to escape into the desert. Yueh also double crosses Baron Harkonnen by implanting a false tooth filled with poisonous gas in the captured Duke’s mouth, instructing Leto that this is the one final act of courage he can undertake—assassinating the Baron through an act of suicide. Leto follows through with the plan but Baron Harkonnen manages to escape alive, although several of his advisors fall to the poison gas.
Idaho dies defending Jessica and Paul; their ally Liet-Kynes is taken prisoner during their escape. Halleck, believing them dead, joins up with a smuggling outfit. Jessica and Paul are on their own, without supplies, in the harsh Arrakis desert. During their escape, Paul inhales a quantity of spice, which enhance his genetics and training to afford him some abilities of foresight with potential futures laid out before him. After arduous travel through the desert in which they survive a sandstorm, an avalanche and a giant sandworm, Paul and Jessica find a Fremen sietch (community) led by Stilgar. The Fremen are a hardy and honorable people who live in communities across the Arrakis deserts that are governed by strict moral, political, and religious codes. Paul proves himself to the Fremen by fighting in single combat, while Jessica proves herself a powerful religious figure who is soon adopted as the sietch’s Reverend Mother. Jessica, who is pregnant with Leto’s daughter Alia Atreides, ingests the Water of Life in the ritual to become Reverend Mother; this change affects Jessica and her unborn child by giving them both the collective ancestral memories of the Fremen Reverend Mothers.
Paul and Jessica learn that the Fremen are more numerous and powerful than commonly thought. The Fremen escape the Emperor’s eye by paying the Guild to largely ignore their movements on Arrakis. They also work to return Arrakis to its ecology with lakes and oceans, a collective goal that drives their individual and societal obsession with reclaiming and storing water from their environments and their own bodies. The Fremen come to view Paul as the messianic figure Mahdi who was promised long ago, although Paul and Jessica recognize this myth as a Bene Gesserit construct planted in Fremen culture. Due to Fremen’s liberal use of spice, Paul’s cognitive abilities continue to develop, while he also becomes physically sharper and stronger due to the tough Fremen lifestyle. Paul is concerned by the visions he has of becoming so powerful that a religious crusade will sweep the galaxy in his name. During his time with Stilgar’s sietch, he also falls in love with a young Fremen woman named Chani.
Meanwhile, Baron Harkonnen persists with his political scheming. He puts his nephew Rabban in charge of Arrakis, but plans to turn Arrakis’s inhabitants against Rabban. This is so that the populace will welcome Feyd-Rautha Harkonnen, the Baron’s favored nephew, as their leader. The Baron has also convinced Hawat, Duke Leto’s Mentat, to work for House Harkonnen by convincing Hawat that it was Lady Jessica who betrayed the Duke.
Two years pass, and the Baron’s ambitions have now grown to aspire to placing Feyd-Rautha on the Emperor’s throne. On Arrakis, Paul has gained increased authority after riding a sandworm, an important mark of adulthood for Fremen men. He teaches Fremen to fight using the “weirding way,” the Fremen name for the Bene Gesserit training Paul has learned from his mother. He gains respect as a Fremen political and religious leader known by the Fremen as “Muad’Dib.” The Fremen ready him to lead a rebellion against House Harkonnen and the Empire to claim back Arrakis. Gurney Halleck is reconnected with Paul when the warrior’s smuggling group is captured by Fremen. Paul also has a child with Chani. Paul’s development into the Fremen’s Mahdi is suddenly compromised when he decides to drink the Water of Life without consulting anyone. No male has ever successfully completed the Fremen’s Water of Life ritual. Paul lies in a coma for three weeks, upon which he awakes with increased mental awareness as the Kwisatz Haderach.
Concerned by the rumors of Fremen leader Muad’dib’s influence, the Harkonnens attack the Fremen with the support of the Emperor’s Sardaukar troops. Astonishingly, the Fremen defeat the Sardaukar forces with little difficulty using wits and tactics that rely on the desert’s harsh conditions. Paul also holds the invaluable spice crops on Arrakis as a ransom that stalls the Empire’s forces.
During the attack, Fremen forces storm the commanding Imperial ship above Arrakis. Here, Alia Atreides kills the Baron Harkonnen, whom she reveals as her grandfather—the Bene Gesserit’s genetic breeding program saw them hide the truth of the Baron’s identity as Jessica’s father. Paul corners the Emperor, demanding that he relinquish the throne to Paul and allow him to marry Princess Irulan. After Paul kills Feyd-Rautha in single combat, the Emperor has no choice but to allow Paul his demands. Paul consoles a hurt Chani that he will never bear children with the Princess. Jessica declares that history will remember Chani and Jessica as Atreides concubines and the true loves of Paul and Leto respectively. In just a few years, then, Paul has assumed political and religious leadership of the Fremen and led them to an unlikely victory against the might of the Empire. However, the violent Fremen holy crusade that Paul has foreseen as a possible future is an unwanted but increasingly likely threat that looms close due to the new power experienced by Muad’dib and the Fremen.
