A glittering alertness came into Duncan's eyes.

"What will you do?" Lucilla asked.

"I have left new marks arranging a rendezvous. Right now, we are all going up to the library. We are going to study the maps. We will commit them to memory. At the very least, we should know where we are when we run."

She gave him the benefit of a curt nod.

Duncan noted her movement with only part of his awareness. His mind already had leaped ahead to the ancient equipment in the Harkonnen library. He had been the one to show both Lucilla and Teg how to use it correctly, calling up an ancient map of Giedi Prime dating from the time when the no-globe had been built.

With Duncan's pre-ghola memory as guide and his own more modern knowledge of the planet, Teg had tried to bring the map up to date.

"Forest Guard Station" became "Bene Gesserit Keep."

"Part of it was a Harkonnen hunting lodge," Duncan had said. "They hunted human game raised and conditioned specifically for that purpose."

Towns vanished under Teg's updating. Some cities remained but received new labels. "Ysai," the nearest metropolis, had been marked "Barony" on the original map.

Duncan's eyes went hard in memory. "That's where they tortured me."

When Teg exhausted his memory of the planet, much was marked unknown but there were frequent curly-ended Bene Gesserit symbols to identify the places where Taraza's people had told Teg he might find temporary sanctuary.

Those were the places Teg wanted committed to memory.

As he turned to lead them up to the library, Teg said: "I will erase the map when we have learned it. There's no telling who might find this place and study it."

Lucilla swept past him. "It's on your head, Miles!" she said.

Teg called after her retreating back: "A Mentat tells you that I did what was required of me."

She spoke without turning: "How logical!"

The worm did not slow its relentless progress until just before dusk.. By then, Odrade had played out her questions and still had no answers. How did Sheeana control the worms? Sheeana said she was not steering her Shaitan in this direction. What was this hidden language to which the desert monster responded? Odrade knew that her Sister-guardians up there in the 'thopters that paced them would be exhausting the same questions plus one more.

Why did Odrade let this ride continue?

They might even hazard a few guesses: She does not call us in because that might disturb the beast. She does not trust us to pluck her party from its back.

The truth was far simpler: curiosity.

The hissing passage of the worm could have been a surging vessel breasting seas. The dry flinty odors of overheated sand, swept across them by a following wind, said otherwise. Only open desert stretched around them now, kilometer after kilometer of whaleback dunes as regular in their spacing as ocean waves.

Waff had been silent for a long period. He crouched in a miniature reproduction of Odrade's position, his attention directed ahead, a blank expression on his face. His most recent statement:

"God guard the faithful in the hour of our trial!"

Odrade thought of him as living proof that a strong enough fanaticism could endure for ages. Zensunni and the old Sufi survived in the Tleilaxu. It was like a deadly microbe that had lain dormant all of those millennia, waiting for the right host to feed its virulence.

What will happen to the thing I planted in the Rakian priesthood? she wondered. Saint Sheeana was a certainty.

Sheeana sat on a ring of her Shaitan, her robe pulled up to expose her thin shanks. She gripped the ring with both hands between her legs.

She had said that her first worm ride went directly to the city of Keen. Why there? Had the worm simply been taking her to her own kind?

This one beneath them now certainly had a different goal. Sheeana no longer questioned but then Odrade had ordered her to remain silent and practice the low trance. That, at least, would assure that every last detail of this experience could be recalled easily from her memory. If there were a hidden language between Sheeana and worm, they would find it later.

Odrade peered at the horizon. The remnant base of the ancient wall around the Sareer was only a few kilometers ahead. Long shadows from it lay across the dunes, telling Odrade that the remnant was higher than she had originally suspected. It was a shattered and broken outline now, with great boulders strewn along its base. The notch where the Tyrant had tumbled from his bridge into the Idaho River lay well to their right, at least three kilometers off their path. No river flowed there now.

Waff stirred beside her. "I heed Thy call, God," he said. "It is Waff of the Entio who prays in Thy Holy Place."

Odrade swiveled her gaze toward him without moving her head. Entio? Her Other Memories knew an Entio, a tribal leader in the great Zensunni Wandering, long before Dune. What was this? What ancient memories did these Tleilaxu keep alive?

Sheeana broke her silence. "Shaitan is slowing."

The remains of the ancient wall blocked their way. It loomed at least fifty meters over the highest dunes. The worm turned slightly to the right and moved between two giant boulders that towered above them. It came to a stop. The long ridged back lay parallel to a mostly intact section of the wall's base.

Sheeana stood and looked at the barrier.

"What is this place?" Waff asked. He raised his voice above the sound of the 'thopters circling overhead.

Odrade released her tiring grip and flexed her fingers. She continued to kneel while she studied their surroundings. Shadows from the tumbled boulders drew hard lines on sand spills and smaller rocks. Seen close up, not twenty meters away, the wall revealed cracks and fissures, dark openings into the ancient foundation.

Waff stood and massaged his hands.

"Why have we been brought here?" he asked. His voice was faintly plaintive.

The worm twitched.

"Shaitan wants us to get off," Sheeana said.

How does she know? Odrade wondered. The worm's movement had not been enough to make any of them stumble. It could have been some private reflex after the long journey.

But Sheeana faced the ancient wall's foundation, sat down on the curve of the worm and slid off. She dropped in a crouch on soft sand.

Odrade and Waff moved forward and watched with fascination as Sheeana slogged through the sand to the front of the creature. There, Sheeana placed both hands on her hips and faced the gaping mouth. Hidden flames played orange light across the young face.

"Shaitan, why are we here?" Sheeana demanded.

Again, the worm twitched.

"He wants all of you off him," Sheeana called.

Waff looked at Odrade. "If God wishes thee to die, He causes thy steps to lead thee to the place of thy death."

Odrade gave him back a paraphrase from the cant of the Shariat: "Obey God's messenger in all things."

Waff sighed. Doubt was plain on his face. But he turned and was first off the worm, dropping just ahead of Odrade. They followed Sheeana's example, moving to the front of the creature. Odrade, every sense alert, fixed her gaze on Sheeana.