Professional Dune Hunting (Ali) 5/25/1433

For three years, the no-ship Ithaca has been in an alternate universe, hiding from the "great enemy". It carries the clones, or gholas, of Duncan Idaho, famous military commander Miles Teg, the Bene Gesserit Sheeana, the last Bene Tleilax Master Scytale, and seven small melange-producing sandworms, as well as a number of other humans. Scytale has shared the secret of producing melange, also called spice, in tanks, because the sandworms do not produce enough to allow the ship to continue travelling. The mysterious Oracle of Time speaks to Duncan and brings the no-ship back into the 'regular' universe. The ship is discovered by the mysterious Daniel and Marty, first mentioned at the end of Chapterhouse: Dune. They attempt to capture the ship, but it escapes.

On Chapterhouse, the only remaining source of spice, Murbella, now the leader of the Honored Matres and Bene Gesserits, is attempting to merge the groups into the New Sisterhood and prevent civil war. Desperate for more spice so that their Navigators can travel through space, the Spacing Guild approaches her, but Murbella refuses, threatening to cut them off completely. Unbeknownst to everyone but the Bene Gesserit, the sandworms on Chapterhouse are not producing much melange; the Bene Gesserit are making up the shortfall with their own stockpiles.

Though the Honored Matres had destroyed all Bene Tleilax worlds, their descendants (the Lost Tleilaxu) have returned from The Scattering. They use the shape-stealing Face Dancers for espionage, until the Face Dancers kill the Tleilaxu Elder Burah and replace him with a duplicate. It is revealed that they have replaced all the Lost Tleilaxu Elders, as well as countless humans on various planets in the Old Empire. Their leader Khrone sends the scribe Uxtal to serve the rebel Honored Matre leader Hellica, who has proclaimed herself Matre Superior and now rules the conquered Bene Tleilax homeworld