Two decades after the release of Dune, Chapterhouse: Dune was released. It was the sixth novel in the series and the last completed by Herbert.

It is thousands of years in the future. Dune itself is no more; the planet has been destroyed by the Honored Matres. The enormously powerful group of women is a dark mirror of the Bene Gesserit, seeking power while that other group seeks enlightenment—and to survive.

The sandworms, bereft of their former world, need a new one. Chapterhouse will be their new home, if the Bene Gesserit can terraform it in time. If their plan succeeds, it will give them full control of the production of that most precious spice, melange. As they work, Mother Superior Darwi Odrade engages in her own vocation: a plot to destroy the Honored Matres.

Among those on Chapterhouse are a clone of Duncan Idaho, and Murbella, his lover. Allowed to enter the Bene Gesserit as a novice, Murbella is suspected of being a spy for The Honored Matres, who would happily see the witches wiped out of existence entirely.

Ghola are clones; built from a few skin cells, they can remember their former lives, and even their moments of death. And there are hive minds, mutants, shape-shifters, biological weapons, interplanetary travel, and more.

In the end, the battle between these two groups comes to a head, with intimate scenes of palace intrigue and scenes of war. That group which would guide humanity to enlightenment faces a group of planet-killers, world-enders, who think nothing of murder if it leads to what they want.