Have you read the Dune books and if so did you understand what they were about after book 1? I didn't get the sequels.
Yeah, I understood them, though reading wiki entries and watching the miniseries has improved my understanding a bit.
In 'Dune Messiah', Muad'Dib has to survive and overcome various plots by his enemies and expresses his despair at how he's become trapped by his own prophecies and by the religious and political system he's created, which he's no longer in control of. His original goal was to lead humanity along a 'golden path'; a chain of events which would avoid the stagnation and extinction of the human race, but he knows this would have a terrible personal cost to himself, so he starts looking for a way out. When his children are born, he loses his prescience, since he only foresaw the birth of a daughter and not twins, and having been previously blinded in a stoneburner attack, he finds his way out. Without his prescience, he's now blind, and under Fremen law, he must walk into the desert to die, which he duly does, leaving the children in the care of his sister.
In 'Children of Dune', the children have reached adolescence and Leto, the male of the pair, is having prophetic visions that he doesn't fully understand. Alia, their aunt and regent, who gained the memories of all her ancestors as a foetus when her mother drank the water of life in the first book, loses her sanity and becomes possessed by her ancestor-memories. Seeing this, the twins, who also were born with the memories of their ancestors, worry that the same fate will befall them. As Alia becomes more violent and oppressive in her rule and rebellion grows, in part spurred on by 'the Preacher', a blind man from the desert who preaches against the religion of Muad'Dib and calls for a return to the old and pure ways, the twins are attacked in a plot by the deposed house Corrino and Leto ends up captured by a rogue tribe of water-thieves, who force-feed him spice esscence in an attempt to make him insane like his aunt. Instead, he overcomes his ancestor memories and achieves prescience, much as his father did in the first book through drinking the water of life. Now prescient, he can see the golden path that his father abortively took, and decides to take up the task himself. To do this, he knows he'll need to live for far longer than a normal human lifespan, so he uses his new-found control over his own biochemistry and his spice saturation to merge a layer of sand trout, larval sandworms, onto his skin, beginning a long transformation into a human-sandworm hybrid that will live for thousands of years. The sand trout give him super-human strength and reflexes, enabling him to easily escape his captors, and he returns to the imperial palace and deposes Alia, taking up the throne as a God Emperor so that he can lead humanity along the golden path.
In 'God Emperor', Leto, who's now transformed into a large sandworm creature with a human face and vestigial limbs, has rendered humanity completely sedentary and helpless through his control of a stockpile of spice, with no more spice production being possible due to the sandworms being extinct due to Arrakis having been terraformed into a moist, green world. He knows he must bring his stewardship of the human race to an end in order to set it free and complete the golden path, and to do this, he uses a Duncan Idaho ghola and one of the descendants of his sister to assassinate him by collapsing a bridge and dropping him into the river below. Leto has by this point begun reversing the terraforming of Arrakis, changing it back to a desert planet, and his death completes the process and begins a new spice cycle, as the sand trout leave his body upon contact with large amounts of water and begin the process of encapsulating the water to make Arrakis dry enough for adult sandworms to survive. Later books deal with the details of the aftermath of his death, and how it leads to mass-famine throughout the empire and a scattering of humanity into unknown space, but I haven't read those.
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