Fielle interrupted, “But we use our minds more than our bodies. The Sisterhood is a philosophy, a way of life, and a way to better the human race.”

Valya raised her voice. “And if we had learned how to fight earlier, we could have been more effective against the Emperor’s troops before they slaughtered so many of us on Rossak. What if Dorotea convinces him to come to Wallach IX and finish the destruction?”

“That would never happen again,” Fielle said.

Valya paused on the path, straightened her back. “I won’t take that chance. I want us to become better fighters, for ourselves and for the Sisterhood.”

Raquella gave her a wry smile. “You are already our best fighter.”

“And I can be better still — and then I can make others better. In each Sister, and in the Sisterhood as a whole, the physical and mental must work together. Each aspect strengthens the other.”

Valya turned to Fielle. “Sometimes I can be a bit abrupt because I am focused on the Sisterhood, on the grand missions and goals that the Mother Superior has laid out for us. I apologize if I seem impatient and overly intense. I am trying to do better.”

Looking sideways, she saw Raquella smiling like a proud parent.

Valya spoke in a rush. After sending Tula on her mission, she had goals of her own, larger plans. “With your permission, Mother Superior, I would like to travel to Ginaz — visit the Swordmaster School and ask them to accept me as a student. Whatever I learn from them can be applied to the Sisterhood.” Valya could also use those skills on behalf of House Harkonnen, perhaps even in personal combat against Vorian Atreides.

Fielle seemed confused by the suggestion, but Raquella gripped the young Sister Mentat’s arm with a withered hand. “Valya’s idea is interesting. You have Mentat training, and it occurs to me that we might learn much from the other great schools as well, adapting their techniques to improve our own.”

Valya squared her shoulders. “Since I’m a Reverend Mother, I can learn more swiftly than others, be better. Let me take them by surprise. I’d like to observe Ginaz, absorb and adapt their fighting methods, bodily control, defenses, and how to think during combat. There is great strength in combining disciplines, and the Sisterhood must have strength. We will be more than a match for Dorotea’s traitors.”

Raquella scolded her like a child. “I may disagree with the others, but they are not traitors, just a different perspective on our teachings. Dorotea has something that we do not — a respected position close to the Emperor. She has no reason to envy us, or fear us. It would be best for our future if we could find common ground. That is what I long for most, before I die.”

Valya tried to control the edge in her voice. “Dorotea should not have betrayed us in the first place, if her true loyalties lay with the Sisterhood.”

“Her loyalties may be confused, but I believe she is still a true Sister in her heart.” Raquella looked sad as she paused on the trail. She turned to Valya. “Just as your blood sister needed to return to your homeworld, I understand that you must go on your own journey. You have my permission to travel to Ginaz.”

Over the years, the scientists on Denali had sent Josef Venport numerous exuberant proposals, many of which had seemed absurd and unobtainable. New shield generators, thoughtrode interfaces, mob stunners, atomic pulse-flashes, even mechanical “cricket” saboteurs.

Not wanting to place limitations on his remote think tank, he told Administrator Noffe to encourage imagination in all its forms, so long as it led to developments that could inflict harm on the Butlerians.

But this was more than he had ever hoped for.

Josef, Draigo, and Ptolemy sat under the bright desert sun watching seven mechanical walkers guided by Navigator brains. He was already impressed with what Ptolemy had produced. The fearsome machines moved with remarkable swiftness and ease. Josef smiled: Results such as this justified the fortune he had poured into the Denali research facility.

Now he had his own Titans.

His great-grandmother had been tortured by one of the ancient Titans, and that ordeal had transformed Norma Cenva into more than a human being. Her husband, Aurelius Venport, had devoted his life to fighting the cymeks. How ironic that Josef Venport was responsible for creating a new group of Titans that were even more powerful than their predecessors.

Ptolemy touched his earadio. “Still no sign of a worm.”

“Maybe the creatures are afraid,” Josef said.

“I doubt sandworms know fear, Directeur,” Draigo said. “From the vibrations, the creatures would have no way of knowing these cymeks were different from a spice factory. And we were anticipating that the Holtzman field from the shields would madden at least one worm.”

“I was being facetious, Mentat.”

At last, a ripple rolled along under the sand, casting it up like the crest of a wave. The great worm plowed through a succession of dunes as if they were no thicker than air, moving with the speed of a projectile fired from a weapon.

Josef rose out of his observation chair. “What a monster!” Beside him, Draigo’s dark eyes widened as he drank in details. Ptolemy looked both awed and terrified.

It seemed that the theories about the effect of shields on the creatures might prove correct after all.

The enraged sandworm exploded upward. As the huge maw came out of the sand, dust sheeted off its curved segments.

Inside their preservation canisters, the proto-Navigator brains did not panic. Having researched the behavior of sandworms, they positioned the walker bodies in a precise attack configuration, as if this were a military drill. Three of the cymeks switched off their shields and bounded away like jumping spiders.

The worm slammed down like a battering ram, but the agile cymeks sprang in opposite directions, their movements carefully coordinated, as if the brains were telepathically linked. Even from the distant outcropping Josef could feel the tremors as the monster dove under the sand.

Scuttling to the dune tops for a better strategic position, the seven cymeks launched artillery, hammering the sandworm’s segmented body with explosion after explosion. So much dust, sand, and smoke boiled into the air that Josef could barely see.

The worm rose up again, thrashing about like an unchecked high-pressure hose. It slammed into one of the cymeks and knocked the machine body into the air, then scooped downward to swallow one of the other cymeks, Hok Evander, who was still protected by a shimmering shield.

In his observation chair, Ptolemy let out a groan as the struggling cymek vanished down the creature’s gullet. Josef was surprised at his lack of objectivity. “This is a test, Dr. Ptolemy. One must expect losses.”

The remaining five Titans redoubled their attack, shooting flames, lasbeams, and exploding shells. Although several of the worm’s armored segments looked ragged and damaged, the attack only enraged the beast. It lifted itself up and then crashed down on top of two more cymeks, smashing them into the sand. The behemoth was so massive that even the walkers’ enhanced armor could not protect them.

The last three Titans spread out equidistant from the worm and continued to attack. The creature let out a rumbling groan like exhaust from a starship engine.

Then, oddly, its serpentine form bulged and swelled, as if repeated detonations were occurring from its interior. A dark stain appeared on the ring segments, then smoke spurted out from a widening wound. Sizzling chemicals dripped down its tough hide.