In the final book of the original Dune trilogy, nine years have passed since Dune Messiah. Alia had become Abomination, as the Bene Gesserit’s had feared, as she became possessed by one of the lives of her ancestors that we part of her cellular structure. It was the Baron Harkonnen who offered her strength when she needed it, but the Baron was always the enemy of House Atreides, and he worked through Alia to wreck the destruction that he failed in life. Lady Jessica had reconciled with the Bene Gesserits, and come back from her haven on Caladan to deal with Alia, and help the Bene Gesserit’s salvage their bloodline in Paul’s twins, his son Leto II and his daughter Ghannima (Ghani).
The twins were being raised at Sietch Tabr under the care of Stilgar, and they had refused to take the spice that was part of Fremen ceremonies, because they wanted to avoid the trap that their father fell into: following the prescient visions lock one into a future which has no surprises or deviations. Having grown up together, even with shared past lives, they understood each other deeply, because they experienced everything together. However, Leto had recently had unbidden prescient visions without spice, like his father Paul had prior to his family coming to Arrakis. The two sat in a niche in the rock and held vigil over the desert one night shortly before Lady Jessica came to figure out what they should do. The book is essentially the plan that they developed.
Both of them prepare Lady Jessica, subtly moving her thoughts into the direction they want her to take. In particular, Leto tells her that she must let herself be kidnapped (which, of course, made no sense to her, but Leto assured her she would understand when the time was right). Now the son of the deposed Emperor Shaddam IV, Farad’n, was a scholar, but his mother was ambitious for him, and had two desert tigers trained to kill two children dressed in particular clothes. (Trained using actual pairs of children as the cats’ victims.) Identical clothes were presented by House Corrino as gifts to the Emperor-to-be and his sister; the twins, knowing the purpose, accepted the clothes. Then, when the time was right, they wore them and sneaked out into the desert around dusk.
They were attacked, just as they expected, and they killed the cats, although not without injury to themselves. After night fell, they said a tearful goodbye, knowing that they would now have diverging experiences and no longer share their original unity. Leto left, and Ghani buried memory of Leto’s escape under such a heavy compulsion that she truly believed him dead by the tigers, and even a Truthsayer would agree that she was telling the truth. When Farad’n's mother told him what she had done for future, he was appalled, and decided that if she was going to go around doing things in his need, he needed to be made ruler of Salusa Secundus. She reluctantly agreed.
The Preacher continued his periodic messages, and in one gave a cryptic message to four people, one of whom was Duncan Idaho, Alia’s husband. Idaho had seen Alia become less and less herself, and with the Preacher’s message, he could no longer pretend that Alia was the person he loved. Somehow the human light had gone out of her eyes and someone cold looked out through them. He accepted Farad’n's offer of betrayal to kidnap Lady Jessica, who remembered what Leto had said (and had grown to realize that Leto was much older than his flesh). Farad’n wanted her to teach him the Bene Gesserit way, which she did. On her suggestion he deposed his mother. However, she also knew that Bene Gesserit training bound you to the Bene Gesserits, and she included that in his training, as well.
Leto went looking for his father, who he knew was the Preacher. (We also find this out, too, when Alia goes incognito to listen to him, and he tells her quietly to “stop interfering, my sister”.) He found the mythical sietch of Jucundu, where he thought his father was, but instead Lady Jessica’s servant Gurney Halleck was there, along with one of the religious cult leaders doing Alia’s bidding. Lady Jessica wanted Halleck to test Leto to ensure that he was in control of his ancestral memories, so that one of them could not possess him. The test consisted of injecting him with spice essence. He did have to battle his ancestral memories, and came to a detente with them, as a collective partnership lead by an ancient ruler. He also had prescient visions, and through these he learned that, while the climate change program started by Liet Kynes was successfully making the planet wetter, it was also killing the sandworms, which needed an extremely arid climate. Of course, without sandworms, there was no spice, and without spice there was no control over the Imperium (and no Imperium, for that matter, as superluminary travel would be impossible without the prescience to choose a safe path). In fact, Alia’s Baron was accelerating the climate change, without her fully realizing it.
Leto was able to escape, even though Alia’s man had slyly cut the circulation pumps on his stillsuit that recycled his water in the desert. He barely found out about it in time. There was a huge sand storm, which he managed to survive by riding a sandworm until it was exhausted, then keeping it on the surface and hiding in its lee. Then he continued to the smuggler’s sietch, where he did find his father. He also found an older girl from one of his visions, and so he had to figure out a way to step off the path of the vision, to keep to the Golden Path of the plan he and Ghani had decided on. The smugglers were planning to enslave him, but he realized that he could escape by making a skin of sand trout. The sand trout were symbiotic with the sand worms, and they encysted any water they came across, since water killed with worms. The sietches protected their green plants with a moat of water filled with carniverous fishes. The sandworms could not cross the water (since they would die), and the sand trout could not survive in the water to encyst it because the fish would eat them. But the sand trout could be smooth over one’s finger, as Fremen children did. Leto just used multiple sand trout to make a thin over-skin.
His new skin quickly bonded with him and gave him immense muscular strength, which took a little time to get used to. He easily escaped the sietch. He was also immune to being eaten by sandworms, as they sensed that he was one of them because of his sandtrout skin and would not come too close to him. The sandtrout skin also acted as a stillsuit, as he could suck a sweet nectar out of his sandtrout skin to rehydrate. He used his new strength to travel quickly to sietches all around and punch unrepairably large holes in their water moats.
Sadly, his father, Paul, was opposed to his plan. Leto’s Golden Path was the horrific path that Paul had been trying to avoid all his life. To Paul, the path involved huge destruction of life in the service of a god, but to Leto the destruction was a lesson that humanity would never forget, not to take the seductive easy path of security that a powerful ruler offered humanity, because that security forces you into someone else’s vision and prevents you from becoming who you really are. In the latter, they were agreed, but Paul could not stomach the means of the lesson. But neither could he argue with someone with the strength of a sandworm.
Leto returned to the capital and spoke the phrase that broke Ghani’s compulsion. Ghani had proposed to marry Farad’n, so that she could kill him and avenge herself on the murder of her brother, and so she was freed from that, too. Leto tried to save Alia, but despite having had a very human moment where she had cried bitterly at realizing that Duncan could no longer lover her, she refused to leave the security of the Baron, and jumped out her high window above the Hajj square instead. The twins had succeeded in their plan (although it had been modified slightly). Ghani had been able to integrate her ancestral memories, and Lady Jessica realized that Abomination was not inevitable of the pre-born, as the Bene Gesserits assumed, and realized that she should tried to help them, since her interventions with Leto had led to an incomplete (but serviceable) integration.
Leto, with his symbiosis with his sandtrout skin, knew he would live for four thousand years before the symbiosis killed him. He told Farad’n that he would cause much bloodshed, and that the terraforming would continue and the sandworms (and spice) die out. This would leave only the dwindling spice reserves of the Spacing Guild and the Great Houses (including his stockpiles). After many years, when they were almost gone, he would dive into the dunes and, as a sandtrout would encyst the water again, so that the sandtrout could become a sandworm and create a flourishing sandworm (and spice) environment. He offered Farad’n to be his court secretary, since his skill was as a historian. He also offered that he could love Ghani (who was quite willing, albeit physically a little young yet), but he and Ghani would continue the Bene Gesserit breeding on their own terms. Farad’n was not very happy with the deal, having sort of wanted to be Emperor himself, and not exactly happy at sharing Ghani. He told Leto this and said he would be restless and try to strike back. Leto replied that this was precisely the point: Leto wanted Farad’n to be uncomfortable, so that he would always speak his mind and so provide Leto with an external check. But Leto said that he and Ghani stood back to back, so when he whispered sweet love to her, his back would be exposed to him.
Children of Dune was good in the first half, while everyone was setting up their plans, and the twins could utter mysterious pronouncements that revealed to the adults that they knew the adults better than the adults did, while the adults did not really fully understand what the twins were talking about. Then the middle upends the success story of Arrakis, that Arrakis can either be wet and pleasant or parched with sandworms and spice, but not both. Also, Jucuntu was basically a torture session (literally; from the plot perspective it appears to be a success for Leto in keeping his ancestral memories in check, that is, until we learn that Ghani managed to healthily integrate them), and the smugglers was an even less attractive place. Then we suddenly learn that you can wear sandtrout (and why did no one else get that bright idea and challenge him?), and that his Golden Path is actually the destructive path that Paul saw.
The major problem is that there was absolutely no hint or preparation for turning the terraforming project from a realization of Fremen dreams into the destruction of Fremen society (which turned out to require harshness) and the sandworms (and spice) altogether. Contrast with Alia: in the first two books Alia is fine, but people react to her assuming that she is Abomination, so we are prepared that something bad could happen (and apparently had, in the past). And Alia was always rather edgy, so when she goes off the rails, it fits with the world as we know it. Whereas the Fremen dream turning into destruction seems arbitrary. Sure, it does capture the unexpectedness of systemic changes and illustrate why we need to fully understand the system before changing it, but the Liet Kynes was an expert, and we are told that he was the one to realize that the sandworms relied on the sandtrout and vice-versa; he was the one who recognized the system in the first place. Sure, it might turn out that the desired revision of the system is not actually consistent with the goals, and even possibly unpredictably so, but none of this was even hinted at. Jurassic Park (the book, not the movie) illustrated that small variations in a system might produce large unexpected effects, but this was consistently communicated. One need not be so direct about it, but without some characters warning about unpredictability, it just seems like Herbert took the Fremen dream away from them because he needed a new revelation for Leto’s prescient visions, even if Herbert actually planned it from the beginning.
By the end, the Dune universe seems very harsh. The old, desert Fremen are pretty explicitly held up as the ideal society, which was created through millenia of oppression, including being driven onto a desert world to eke out an existence, where the struggle to survive produced human vitality. Contrast with the soft, younger Fremen, who were turning into the world around them, which just enjoyed their comfortable float down the river of life, following the path laid out for them instead of finding their own identity. So the passiveness is a problem, and the harshness of House Corrino and House Harkonnen, and the conniving of the Bene Gesserits is frowned upon, but both Paul and, in the future, Leto, inflicted more death on humanity than anyone before them, but that is the Golden Path? At least Paul was sorry that he could not find a better way, having been sort of carried along by humanity’s worship of safety and order. Where are the Atreides’ values? Leto basically says that he does a good thing, being an example that is so bad that everyone will avoid it in the future.
I kind of get the logic, but it is pretty strained. Surely there is at least a middle path, where there might be no other choice, but the characters are appalled by the destruction and fight it, even if pyrrhicaly. Or maybe there is some hope besides a memory so bad that it is seared into human collective consciousness like the Butlerian Jihad which was so destructive that thinking machines were forbidden as a universal religious commandment. There is Christian hope, of supreme sacrifice, which leads to Christ’s followers being given a new heart, becoming a new creation, one that can willingly and perfectly (albeit imperfectly now) live out the life of sacrifical love that Christ modeled. The implication is that when we all love on another, and the greatest among you is the servant of all, that is the glorious hope of humanity. But even if that is philosophically objectionable, could there be some way where the dreams of humanity are fulfilled, at least partially? Instead, even the main characters give sacrificially, but for Paul it does not work (he did not die when he walked out in to the desert) and for Leto, he is in constant pain for four thousand years, and will inflict pain on humanity, and then best we get is that we do not forget the lesson. Even Buddhism does better than that—sure, life is unrelenting pain, but at least it is possible to escape the cycle into nothingness.
I like the planning parts, and I even like the intrigue. But the philosophy is dismal, and there is just so much arbitrary upending. Terraforming is good; now it is bad. Fremen finally begin seeing their dream of a pleasant world beginning to be fulfilled, even though it is generations distant; now their dream is unattainable. Paul finally succeeded in stepping off the path of his visions; actually, nope, he is still enslaved to them. Paul at least avoided terrific suffering for humanity; nope, that is the only way humanity will learn. And to top it all off, Leto is now effectively a god, since he is unbelievably strong and lives for thousands of years, but he is a harsh god, one who makes his closest advisor choose between intimacy with his love or safety from being stabbed in the back, an oyster with a sharp grain of rock that cannot ever be made into a pearl.
As Herbert’s son noted, the story of the Atreides family is a tragedy. Yes, but it is more than that: it is a tragedy where not only all the main characters die, but everyone else suffers, too, and just barely makes it. In fact, the tragedy is arguably humanity itself, which loves safety so much that it stifles itself, and the only cure is millenia of suffering. But as a reader, the tragedy is that the world is compelling and the characters lovable ... until they become monsters.