Twelve years after the events described in Dune, Paul Atreides rules as Emperor of the Known Universe, following a universal jihad he unleashed by accepting the role of Messiah to the Fremen. While Paul is the most powerful Emperor ever known, he is ironically powerless to stop the lethal religious excesses of the juggernaut he has created.
Although sixty-one billion people have perished, Paul's prescient visions indicate that this is far from the worst possible outcome for humanity. Motivated by this knowledge, Paul hopes to set humanity on a course that will not inevitably lead to stagnation and destruction, while at the same time acting as ruler of the Empire and focal point of the Fremen religion.
The situation is further complicated by the conspiracy of powerful interests who hope to reverse the events that brought House Atreides to the throne, including the remnants of the displaced House Corrino, the Bene Gesserit who have lost control of their Kwisatz Haderach, the Spacing Guild (now utterly beholden to Paul), and the Bene Tleilax. The Atreides dynasty is unstable because Paul has not produced an heir. Seeking to force Paul to sire a child with her, his consort the Princess Irulan has been secretly giving contraceptives to his beloved concubine, Chani. Paul is aware of this, but he has foreseen that the birth of his heir will bring Chani's death, and he does not want to lose her. Chani then conceives after switching to a traditional Fremen fertility diet, preventing Irulan from being able to tamper with her food.
The conspirators, including Bene Gesserit Reverend Mother Gaius Helen Mohiam, Guild Navigator Edric, the Tleilaxu Face Dancer Scytale, and Princess Irulan, give Paul a gift he cannot resist: a Tleilaxu-grown ghola of Duncan Idaho, his childhood teacher and friend, now called "Hayt". The conspirators hope the presence of Hayt will undermine Paul's ability to rule by forcing Paul to question himself and the empire he has created. Furthermore, Paul's acceptance of the gift weakens his support among the Fremen, who see the Tleilaxu and their tools as unclean.
Further complicating the situation is the physical maturity of Paul's powerful sister, Alia, who finds herself irresistibly attracted to Hayt/Duncan. Alia and Hayt investigate the appearance of a female corpse near the city; Hayt realizes that no-one having been reported missing implies a Tleilaxu plot in which the woman has been replaced by a Face Dancer. Hayt also takes this opportunity to steal a kiss from Alia. She is outraged, but Hayt just laughs that he took nothing more than she offered, a fact she admits to herself privately.
"Brilliant . . . It is all that DUNE was, and maybe a little more." (Galaxy Magazine)
