These summeries are so long because a lot happens in these books.
Wishing to beter understand the mysterious spice Melange, The Emperor dispatches the Imperial planetologist Pardot Kynes to Arrakis to uncover the secrets of the spice. There, the plantetologist comes up with an idea on how to someday make Arrakis a lush, green planet. Out in the desert, he saves some Fremen from being killed by a Harkonnen patrol. Curious about these people, he enters into their tribe. However, Fremen typically don't trust outsiders and the tribe leader orders Kynes to be killed. But after Kynes tells them about his dreams of making Arrakis green with life, the Fremen consider him to be no less than a prophet sent by God. Calling him "Umma Kynes" (Prophet Kynes), the Fremen take on his dream as their own holy mission. With the thousands of Fremen living on the planet, Kynes now has the workers he needs to begin changing the face of Arrakis. Still, it would take decades, even centuries to make his dream a reality. Kynes also marries a Fremen woman, and together they have a son, Liet. This boy could one day take over Kynes' work and continue his dream.
Leto Atreides is sent by his father, Duke Paulus Atreides, to the machine planet of Ix to study for one year. Staying in the custody of Earl Dominic Vernius, Leto becomes friends with the Earl's children, Rhombur and Kailea Vernius. Leto's trip is cut short when the Tleilaxu begin an attack on Ix. They claim that the Ixians have broken ancient law by constructing a machine that has the ability to think like a human. But that is only an excuse to allow the Tleilaxu to conquer Ix and gain access to its advanced technology. In actuality, the Tleilaxu need Ixian technology to carry out a secret project supported by the Emperor, the development of an artificial form of the spice. After the attack, Earl Vernius and his wife flee into hiding, and Leto escapes ,with Rhombur and Kailea, back to his home planet Caladan.
On the planet Giedi Prime, an eight-year-old Harkonnen slave, named Duncan Idaho, watches as his family is killed. He is then taken away to act as hunting prey for the Baron's nephew, Glossu Rabban. What started out as a game becomes a fight for his life as Ducan tries to escape the Harkonnen hunters. He is eventually able to outsmart his would be killers, and escapes onboard a ship that takes him to Caladan. Very eager to serve House Atreides, he is taken into the castle as a servent. While tending the stables, he notices that one of the Salusan bulls is behaving strangely. This happened to be the bull that Duke Paulus was to fight in an upcoming bullfight. Ducan voices his concerns to the stablemaster, but instead of warning the Duke, the stablemaster locks Duncan up. Unaware that the bull was drugged, Duke Paulus goes on with the bullfight. The old Duke is killed, and suddenly Leto realizes that he is now Duke of House Atreides.
For centuries, the Bene Gesserit Sisterhood has carried out a secret breding program to produce a superbeing known as the Kwisatz Haderach. For the next step, they required Harkonnen blood, specifically, the bloodline of Baron Vladimir Harkonnen. Reverend Mother Gaius Helen Mohiam is sent to the Baron to be the mother of his child. Very reluctantly, he agrees to father the child, but just this once. However, the child that is born turns out to be very weak and fragile. Reverend Mother Mohiam knew that there was no way this child could produce the daughter, who would produce the Kwisatz Haderach. She would have to go back to the Baron and try again. The Baron is outraged, so he attacks and brutally rapes the Reverend Mother. She retaliates by giving the Baron a disease that would slowly destroy his muscles and make him extremely fat. Although, not the way she had intended, Mohiam now had the child she needed. With the birth of this child, named Jessica, the Bene Gesserit were now only two generations away from producing the Kwisatz Haderach.
On Caladan, young Leto's skills are quickly put to the test. Earl Vernius is missing, his wife, Shando, has been killed, and House Vernius has been declared renegade. Rhombur and Kailea remain under Leto's protection. Also, Leto discovers that his father was murdered, and that a key player in the murder plot was his own mother, Lady Helena Atreides. Leto knew that his parents never loved each other, but he couldn't believe that his mother would plot against his father. He orders his mother sent away. Next, Leto travels to the Imperial capital planet, Kaitan, to address the Landsraad Council. On the way, Leto falls right in the middle of another plot, this time set up by his family's mortal enemies, the Harkonnens. The Harkonnens have gained possesion of an experimental "no-ship". This ship, which is completely invisible, allows Rabban to attack a Tleilaxu ship, but to make it look like Leto's ship had fired. The Baron is certain that he had started a war between the Tleilaxu and House Atreides and could finally eliminate his enemies once and for all. Leto is put on trail before the Landsraad Council and all of the evidence is against him. However, the charges against Leto are dropped thanks to help from his cousin, Crown Prince Shaddam.
The Emperor's doctors are completely baffled by his change in health. However, Fenring's poison takes to long. Eventually, Fenring murders Elrood IX himself. The Padishah Emperor Shaddam IV assumes the throne. He marries the Bene Gesserit Anirul and appoints Count Hasimir Fenring Imperial Observer on Arrakis. And, the Renegade Earl Dominic Vernius sets up a new base on Arrakis. With the help of a group of smugglers, he prepares to fight back against the Imperium that destroyed his family.
Baron Vladimir Harkonnen continues to hold the governership of Arrakis, seeking to make as much profit in spice mining as possible. He also has to deal with his own health problems. None of his doctors have been able to identify the mysterious illness that has afflicted him (That's why most of his doctors are dead). Finally, he hires a Suk doctor named Wellington Yueh. With Dr. Yueh's help, the Baron figures out that it was Reverend Mother Mohiam who gave him the disease. He immediately prepares for an attack on the Bene Gesserit planet, Wallach IX. The Baron takes several of his troops down to the planet to capture Mohiam by force, but they come up empty handed. Finally, the Baron's nephew, Rabban, takes matters into his own hands by stealing the experimental no-ship and carrying out his own raid. As a result, he, and the no-ship, are captured. When they discover the no-ship, the Bene Gesserit realize how dangerous this ship could be, and how the Harkonnens had used it to incriminate Leto Atreidies. They make a deal with the Baron. They would release Rabban, and not tell about the no-ship, but the Baron could not have Reverend Mother Mohiam. The Baron then returns to Giedi Prime but sends his disgraced nephew of to Lankiveil.
Gurney Halleck has spent his whole life as a Harkonnen slave. Although, he lives a hard life, his spirits remain high and he always has a song to play on his trusty baliset. Until one day, a Harkonnen patrol breaks into his house and takes away his sister, Bheth. Although, his parents ignore the incident, Gurney spends years trying to find her. During this time, he also becomes more and more rebellious against the Harkonnens, and his beatings become worse and worse. At one point, he even attacks the Baron's nephew, Glossu Rabban. As a result, Gurney's parents are murdered and his sister is raped and killed in front of him. Gurney eventually escapes from Giedi Prime, joins a group of smugglers, and later offers his services to House Atreides.
A young Ixian, named C'tair Pilru, has spent 10 years fighting against the Tleilaxu occupation as a member of an underground resistance movement. However, their fight becomes much more difficult as the Emperor sends in his own Sardaukar troops to guard the Tleilaxu project. Meanwhile, Rhombur and Kailea Vernius are still on Caladan under Duke Leto's protection. Rhombur is very anxious to help his people, so with Leto's permission, he begins to supply the resistance with explosives. As for Kailea, she falls in love with Duke Leto, and he takes her as a concubine. As this is going on, Duncan Idaho begins his 8 years of training to become one of the legenday Swordmasters of Ginaz. On Ix, the fight does not go well. The entire resistance movement is hunted down and killed by the Sardaukar, and C'tair is forced to continue the fight alone.
The planet Lankiveil is home to Baron Vladimir's half brother, Abulurd. Unlike the Baron, who is only interested in increasing House Harkonnen's power, Abulurd tries to make life easier on the citizens of his planet. His son, Glossu Rabban, hates him because of this weakness. Abulurd begins to spend Harkonnen profits to provide relief for his people. This angers the Baron, and Rabban is sent to convince Abulurd that his first responsibility is to House Harkonnen. Rabban terrorizes the people of Lankiveil by leading several raids. Eventually, Abulurd gives up his Harkonnen name, and he and his wife, Emmi, have another son, Feyd-Rautha. They were determined to raise this boy right so he wouldn't turn out like Rabban. But, The Baron orders Rabban to take the child away to be raised on Giedi Prime. Rabban later takes his final revenge and strangles his own father to death. This earns Glossu Rabban his new name, "Beast" Rabban.
On Arrakis, Pardot Kynes continues his work, as his son Liet grows up surrounded by Fremen culture. Liet, and his best friend Warrick, take part in several raids against the Harkonnens. While on a errand for the tribe, the two young Fremen, come across a smuggler base, and meet the former ruler of Ix, Earl Dominic Vernius. Liet helps him out by teaching him how to better camouflage the base. Years later, both Warrick and Liet fall in love with the same woman, Faroula. She ends up marrying Warrick. Seeking to get away for a little while, Liet joins the smugglers for about a year. Shortly after he returns to Dune, Warrick dies and Liet marries Faroula. Meanwhile, Earl Vernius returns to Ix and can't believe what the Tleilaxu have done to it. He vows revenge against the man responsible, The Padishah Emperor. As he prepares for a massive assault on Kaitain, the smuggler base is attacked by the Sardaukar. As his final act of defiance, Earl Dominic Vernius destroys the base, killing himself and all of the invading Sardaukar.
Leto and Kailea have a son, Victor. But the love between Leto and Kailea begins to fade away. Kailea has always dreamed of living in the Imperial Court on Kaitan. These dreams are further fueled by her lady-in-waiting, Chiara, who tells her stories of the glamorous, Imperial life. As time goes on, Kailea listens to Chiara's advice and becomes more and more hateful of Duke Leto. To make matters worse, the Bene Gesserit have ordered one of their sisters, Jessica, to live in the castle. Jessica's mission is to bare Duke Leto's daughter, who will one day give birth to the Kwisatz Haderach. As things worsen between Leto and Kailea, Leto spends more time with Jessica. Although, she is not supposed to feel anything for Leto, she falls in love with him, and for some reason, choses not to bare a daughter. Finally, Kailea's hatred becomes so great that she gives permission for Chiara to eliminate Leto and make young Victor the new Duke. But the plot goes terribly wrong. Instead, six year old Victor is killed in an explosion, and Rhombur is severely injured with most of his body destryed. Completely devastated at what she had allowed to happen, Kailea discovers that Chiara is a Harkonnen spy who had been plotting to turn her against Duke Leto all this time. Kailea Vernius kills the spy and then takes her own life.
Leto is then faced with the most difficult decision of his life. He receives an offer from the Tleilaxu, they will create a clone of his son, Victor, but only if Leto would turn Rhombur Vernius over to them. To turn over his best friend to get his son back, Leto agonized over this decision and nearly went through with the deal. He finally decided that the price was too high and refused.
After completing 8 years of grueling training and helping to fend off an attack on Ginaz, Duncan Idaho returns to Caladan as a Swordmaster. The Baron, now needing the help of suspensors just to walk, begins to raise young Feyd-Rautha as a true Harkonnen. Pardot Kynes is killed in an accident, Liet-Kynes takes over the duties of the Imperial planetologist and vows to continue his father's dream. The Emperor's servent, Count Hasimir Fenring, finds out that the Tleilaxu have almost completed their project on Ix. Leto hires Dr. Wellington Yueh to construct a cybornetic body for Rhombur. And against her Bene Gesserit orders, Jessica vows to bare Leto another son.
The first world to be attacked is Zanovar. However, an illegal spice hoard is not the only reason Emperor Shaddam orders the attack. He has learned that his father, Elrood IX, had an illegitmate son named Tyros Reffa, who happened to live on Zanovar. Reffa represents a threat to the Emperor's throne so Shaddam orders the whole planet devastated in the hopes of eliminating him. Reffa was not on the planet during the attack, but when he learns what the Emperor has done, just to get to him, he swears vengeance. He attempts to assassinate Shaddam on Kaitain. The attempt fails and Reffa is captured and executed.
On Ix, the Tleilaxu begin to test samples of the new amal. The leader of the project, Hidar Fen Ajidica, assures the Emperor he will begin to distribute the spice substitute soon. But the Tleilaxu leader has plans of his own. He has no intention of handing the amal over to the Emperor, instead he hopes to use it to gain power for himself. As part of this plan, the Tleilaxu exume the bodies from an Atreides war memorial on Beakkal. They hope to obtain cellular material from the bodies to create Atreides clones. Atreides forces, under the command of Duncan Idaho, destroy the memorial rather than allow the bodies to fall into Tleilaxu hands. Ajidica continues his plot by giving out samples of amal to the Sardaukar guarding the project, addicting them to ensure their loyalty. To test whether the Guild navigators can use amal as they do melange, amal is brought aboard two Guild highliners. This test is a disaster as one highliner crashes and the other is left stranded out in deep space. Still hoping to achieve his goals, Ajidica sends Tleilaxu face dancers to key locations throughout the Imperium to help him seize power when the time comes.
Duke Leto Atreides, still coming to terms with the death of his son Victor, decides that the time is right to overthrow the Tleilaxu occupation of Ix and return it to it's rightful leader, his friend Prince Rhombur. Rhombur, with the help of his new cybernetic body, decides to led the liberation himself. Accompanied by Gurney Halleck, he travels to Ix to make contact with the rebel C'tair Pilru and start an underground uprising while Atreides forces attack at the same time. However, Rhombur and Gurney are delayed when thier highliner is stranded out in space. Poisoned by the amal, the navigator returns the ship to Imperial space but dies from the effort. Meanwhile, on Arrakis, Liet-Kynes becomes the leader of all the Fremen tribes. He orders the Fremen to continue attacks against the Harkonnens who control the planet. To strike a great blow against the Baron, Liet informs the Guild that the Harkonnens posses illegal stockpiles of spice. He hopes that with this information, The Emperor will remove the Harkonnens from Arrakis.
A few months away from giving birth to Leto's son, Lady Jessica is summoned to Kaitain where the Bene Gesserit can oversee the birth of this very important child. Bene Gesserit mother Anirul, wife to the Emperor and overseer of the Kwisatz Haderach breeding program, tells Jessica about the program and how her child will be the mother of the Kwisatz Haderach. But against the Bene Gesserit's wishes, Jessica was going to give birth to a son not a daughter. Anirul senses that something is wrong and Jessica becomes fearful for her child's life. Meanwhile, Richese and Beakkal become the next two worlds to fall victem to the Spice War. As a display of Atredies honor, Duke Leto sends relief supplies to both worlds, even though he had attacked Beakkal earlier. Sending his trusted survent, Thufir Hawat to lead the relief effort, Leto travels to Kaitain to explain these actions as they are happening. With these efforts, the Duke hopes to draw attention away from the upcoming battle to retake Ix.
Count Fenring discovers that amal doesn't work like melange, and that it was in fact responsible for the two highliner accidents. He returns to Ix to confront Hidar Fen Ajidica. Being no match for Ajidica's spice addicted Sardaukar, Fenring is captured and a face dancer disguised as Fenring present a report to the Emperor claming that the amal project has been completed and the artificial spice is ready to be distributed. The only thing left for Shaddam to do is to destroy the production of melange to make amal the only available spice, giving the Emperor absolute power. He has reason to suspect that the Harkonnens not only have illegal spice stockpiles on Arrakis, but they were also responsible for poisoning the spice that led to the highliner accidents. This presents the perfect opportunity to destroy Arrakis and the spice with it. The Emperor himself leads the large Imperial fleet that will level the planet. As he is about to give the attack order, the Spacing Guild intervenes. They will not allow the spice that they rely on to be destroyed and threaten to leave Shaddam and his fleet stranded over Arrakis forever. With no choice, the Emperor orders his fleet to stand down.
Prince Rhombur leds his people in the revolt to retake their world from the Tleilaxu. C'tair sets explosives to disable the Tleilaxu defenses, allowing Duncan to lead the full might of the Atreides military to support the Ixians from above. The combined forces battle against Tleilaxu and Sardaukar. During the battle, the rebels discover cases of the artificial spice. Hoping to relay this information to the Guild, C'tair attempts to send out a telepathic message using a special transmitter he had constructed. The device overloads and he is killed. As the battle continues, Fenring watches as Hidar Fen Ajidica dies from the amal he had consumed. Knowing that the project to create an alternative to spice was a complete falure, he destroys the research pavilion, and with it all the evidence of the project. Then all of a sudden, hundreds of Guild ships appear over Ix. Having received C'tair message, they officially recognize Rhombur as the leader of Ix.
With all of the Atreides forces fighting on Ix, Caladan is left vulnerable. Glossu "Beast" Rabban joins forces with Viscount Moritani to launch a combined Harkonnen / Gumman attack against Caladan. Using a fleet of unmarked warships, they hope to take control of the planet before Duke Leto's forces can return from Ix. Luckily, Thufir Hawat arrives in time to deceive the attackers into thinking that more Atreides forces are present than they had expected. The attacking fleet withdraws. Back on Kaitain, Jessica gives birth to a baby boy. The Bene Gesserit are disappointed with Jessica's failure, but they allow the child to live. As a matter of fact, Anirul senses something unusual with the newborn child, opening her mind to the possibility that the Kwisatz Haderach may have arrived a generation early. However, the child is kidnapped and Anirul is murdered. Reverend Mother Mohiam kills the kidnapper and rescues the boy.
House Vernius is restored with Rhombur as it's new Earl. After twenty years under Tleilaxu occupation, the people of Ix can begin the process of rebuilding their planet. At a gathering of the Landsraad, Duke Leto Atreides speaks on behalf of the disgraced Emperor. As a result, the Padishah Emperor Shaddam IV is allowed to remain on the throne, but his powers are to be limited for a time and advisors will be assigned to assist him. Duke Leto later returns home with Jessica and their newborn son. He is named Paul Orestes Atreides, the heir to House Atreides. And on Arrakis, Liet-Kynes and the Fremen witness a great omen, believing that "somewhere in the universe, an important birth had occurred, one that would be hailed across millennia to come."