That is where it happened!
Odrade stopped and let the image projections have their way with her awareness. Warning! Something dangerous had been identified. She did not try to dig out the warning's substance. If she did that, she knew it could fall apart in skeins, any one of which might be relevant, but the original certainty would vanish.
This thing out there was fixed in the Atreides history. Leto II, the Tyrant, had fallen to his dissolution from that faery bridge. The great worm of Rakis, the Tyrant God Emperor himself, had been tumbled from that bridge on his wedding peregrination.
There! Right there in the Idaho River beneath his destroyed bridge, the Tyrant had been submerged in his own agony. Right there, the transubstantiation from which the Divided God was born - it all began there.
Why is that a warning?
Bridge and river had vanished from this land. The high wall that had enclosed the Tyrant's dryland Sareer was eroded into a broken line on a heat-shimmering horizon.
If a worm came now with its encapsulated pearl of the Tyrant's forever-dreaming memory, would that memory be dangerous? So Taraza's opposition in the Sisterhood argued.
"He will awaken!"
Taraza and her advisors denied even the possibility.
Still, this claxon from Odrade's Other Memories could not be shunted aside.
"Reverend Mother, why have we stopped?"
Odrade felt her awareness lurch back into an immediate present that demanded her attention. Out there in that warning vision was where the Tyrant's endless dream began but other dreams intruded. Sheeana stood in front of her with a puzzled expression.
"I was looking out there." Odrade pointed. "That was where Shai-hulud began, Sheeana."
Waff stopped at the end of the causeway, one step short of the encroaching sand and now about forty paces ahead of Odrade and Sheeana. Odrade's voice brought him to stiff alertness but he did not turn. Odrade could feel the displeasure in his posture. Waff would not like even a hint of cynicism directed at his Prophet. He always suspected cynicism from Reverend Mothers. Especially where religious matters were concerned. Waff was not yet ready to accept that the long-detested and feared Bene Gesserit might share his Great Belief. That ground would have to be filled in with care-as was always the way with the Missionaria Protectiva.
"They say there was a big river," Sheeana said.
Odrade heard the lilting note of derision in Sheeana's voice. The child learned quickly!
Waff turned and scowled at them. He heard it, too. What was he thinking about Sheeana now?
Odrade held Sheeana's shoulder with one hand and pointed with the other. "There was a bridge right there. The great wall of the Sareer was left open there to permit the passage of the Idaho River. The bridge spanned that break."
Sheeana sighed. "A real river," she whispered.
"Not a qanat and too big for a canal," Odrade said.
"I've never seen a river," Sheeana said.
"That was where they dumped Shai-hulud into the river," Odrade said. She gestured to her left. "Over on this side, many kilometers in that direction, he built his palace."
"There's nothing over there but sand," Sheeana said.
"The palace was torn down in the Famine Times," Odrade said. "People thought there was a hoard of spice in it. They were wrong, of course. He was much too clever for that."
Sheeana leaned close to Odrade and whispered: "There is a great treasure of the spice, though. The chantings tell about it. I've heard it many times. My... they say it's in a cave."
Odrade smiled. Sheeana referred to the Oral History, of course. And she had almost said: "My father..." meaning her real father who had died in this desert. Odrade already had lured that story from the girl.
Still whispering close to Odrade's ear, Sheeana said: "Why is that little man with us? I don't like him."
"It is necessary for the demonstration," Odrade said.
Waff took that moment to step off the causeway onto the first soft slope of open sand. He moved with care but no visible hesitation. Once on the sand, he turned, his eyes glistening in the hot sunlight, and stared first at Sheeana and then at Odrade.
Still that awe in him when he looks at Sheeana, Odrade thought. What great things he believes he will discover here. He will be restored. And the prestige!
Sheeana sheltered her eyes with one hand and studied the desert.
"Shaitan likes the heat," Sheeana said. "People hide inside when it's hot but that's when Shaitan comes."
Not Shai-hulud, Odrade thought. Shaitan! You predicted it well, Tyrant. What else did you know about our times?
Was it really the Tyrant out there dormant in all of his worm descendants?
None of the analyses Odrade had studied gave a sure explanation of what had driven one human being to make himself into a symbiote with that original worm of Arrakis. What went through his mind in the millennia of that awful transformation? Was any of that, even the smallest fragment, preserved in today's Rakian worms?
"He is near, Mother," Sheeana said. "Do you smell him?"
Waff peered apprehensively at Sheeana.
Odrade inhaled deeply: a rich swelling of cinnamon on the bitter flint undertones. Fire, brimstone - the crystal-banked inferno of the great worm. She stooped and brought up a pinch of blown sand to her tongue. All of the background was there: the Dune of Other Memory and the Rakis of this day.
Sheeana pointed at an angle to her left, directly into the light breeze from the desert. "Out there. We must hurry."
Without waiting for permission from Odrade, Sheeana ran lightly down the causeway, past Waff and out onto the first dune. She stopped there until Odrade and Waff caught up with her. Off the dune face she led them, up another with sand clogging their passage, out along a great curving barracan with wisps of dusty saltation blowing from its crest. Soon, they had put almost a kilometer between themselves and the water-girded security of Dar-es-Balat.