By the time of this volume, battles and plagues have nearly destroyed humans and their planets. Sheanna revives the ghola cloning project to pit genius against numbers. Almost all the saga principals have been re-created—Paul, Jessica, Letos I and II, Chani, Stilgar, even Wellington Yueh and Baron Harkonnen are hiding on the no-ship. The eleventh ghola of Duncan Idaho keeps an eye on things. Naturally, such a crew generates intrigue, dissension, and many actions unintentionally at cross-purposes. Some of the re-creations learn from the past, some don t. Meanwhile, Omnius and Erasmus, leaders of the thinking machines, search for the no-ship; failing to find it, they finish the destruction of any planet capable of supporting human life. When the clones and the thinking machines finally confront each other, the conflict proves pretty gripping.