It was much hotter in front of the gaping mouth. The familiar bite of melange filled the air around them.

"We are here, God," Waff said.

Odrade, getting more than a little tired of his religious awe, spared a glance for their surroundings - the shattered rocks, the eroded barrier reaching into the dusky sky, sand sloping against the time-scarred stones, and the slow scorching huff-huff of the worm's internal fires.

But where is here? Odrade wondered. What is special about this place to make it the worm's destination?

Four of the watching 'thopters passed in line overhead. The sound of their wing fans and the hissing jets momentarily drowned out the worm's background rumblings.

Shall I call them down? Odrade wondered. It would take only a hand signal. Instead, she lifted two hands in the signal for the watchers to remain aloft.

Evening's chill was on the sand now. Odrade shivered and adjusted her metabolism to the new demands. She felt confident that the worm would not engulf them with Sheeana beside them.

Sheeana turned her back on the worm. "He wants us to be here," she said.

As though her words were a command, the worm twisted its head away from them and slid off through the tall scattering of giant boulders. They could hear it speeding away back into the desert.

Odrade faced the base of the ancient wall. Darkness would be upon them soon but enough light remained in the high desert's long dusk that they might yet see some explanation of why the creature had brought them here. A tall fissure in the rock wall to her right seemed as good a place to investigate as any. Keeping part of her attention on the sounds from Waff, Odrade climbed a sandy incline toward the dark opening. Sheeana kept pace with her.

"Why are we here, Mother?"

Odrade shook her head. She heard Waff following.

The fissure directly in front of her was a shadowy hole into darkness. Odrade stopped and held Sheeana beside her. She judged the opening to be about a meter wide and some four times that in height. The rocky sides were curiously smooth, as though polished by human hands. Sand had drifted into the opening. Light from the setting sun reflected off the sand to bathe one side of the opening in a wash of gold.

Waff spoke from behind them: "What is this place?"

"There are many old caves," Sheeana said. "Fremen hid their spice in caves." She inhaled deeply through her nose. "Do you smell it, Mother?"

There was a definite melange odor to the place, Odrade agreed.

Waff moved past Odrade and into the fissure. He turned there, looking up at the walls where they met in a sharp angle above him. Facing Odrade and Sheeana, he backed farther into the opening, his attention on the walls. Odrade and Sheeana stepped closer to him. With an abrupt hissing of spilled sand, Waff vanished from their sight. In the same instant, the sand all around Odrade and Sheeana slipped forward into the fissure, dragging both of them with it. Odrade grabbed Sheeana's hand.

"Mother!" Sheeana cried.

The sound echoed from invisible rock walls as they slid down a long slope of spilling sand into concealing darkness. The sand drifted them to a stop in a final wash of gentle movement. Odrade, in sand up to her knees, extricated herself and pulled Sheeana with her onto a hard surface.

Sheeana started to speak but Odrade said: "Hush! Listen!"

There was a grating disturbance off to the left.

"Waff?"

"I'm in it up to my waist." There was terror in his voice.

Odrade spoke dryly. "God must want it that way. Pull yourself out gently. It feels like rock under our feet. Gently now! We don't need another avalanche."

As her eyes adjusted, Odrade looked up the sand slope down which they had tumbled. The opening where they had entered this place was a distant slit of dusky gold far away above them.

"Mother," Sheeana whispered. "I'm scared."

"Say the Litany Against Fear," Odrade ordered. "And be still. Our friends know we are here. They will help us get out."

"God has brought us to this place," Waff said.

Odrade did not respond. In the silence, she pursed her lips and gave a high-pitched whistle, listening for the echoes. Her ears told her they were in a large space with some sort of low obstruction behind them. She turned her back on the narrow fissure and gave another whistle.

The low barrier lay about a hundred meters away.

Odrade freed her hand from Sheeana's. "Stay right here, please. Waff?"

"I hear the 'thopters," he said.

"We all hear them," Odrade said. "They are landing. We will have help presently. Meanwhile, please stay where you are and remain silent. I need the silence."

Whistling and listening for the echoes, placing each foot carefully, Odrade worked her way deeper into the darkness. An outstretched hand encountered a rough rock surface. She felt along it. Only about waist high. She could feel nothing beyond it. The echoes of her whistles said it was a smaller space there and partly enclosed.

A voice called from high behind her. "Reverend Mother! Are you there?"

Odrade turned, cupped her hands around her mouth and shouted: "Stay back! We've been spilled into a deep cave. Bring a light and a long rope."

A tiny dark figure moved back out of the distant opening. The light up there was growing dimmer. She lowered her cupped hands and spoke into the darkness.

"Sheeana? Waff? Come toward me about ten paces and wait there."

"Where are we, Mother?" Sheeana asked.

"Patience, child."

A low, muttering sound came from Waff. Odrade recognized the ancient words of the Islamiyat. He was praying. Waff had dropped all attempts to conceal his origins from her. Good. The believer was a receptacle for her to feed with the sweets of the Missionaria Protectiva.

Meanwhile, the possibilities of this place where the worm had brought them excited Odrade. Guided by one hand on the rock barrier, she explored along it to her left. The top was quite smooth in places. All of it sloped inward away from her. Other Memories offered a sudden projection:

Catchbasin!

This was a Fremen water storage basin. Odrade inhaled deeply, testing for moisture. The air was flint dry.

A bright light from the fissure stabbed downward, driving away the darkness. A voice called from the opening and Odrade recognized it as one of her Sisters.

"We can see you!"

Odrade stepped back from the low barrier and turned, peering all around. Waff and Sheeana stood about sixty meters away staring at their surroundings. The chamber was roughly circular, some two hundred meters in diameter. A rock dome arched high overhead. She examined the low barrier beside her: yes, a Fremen catchbasin. She could discern the small rock island in its center where a captive worm could be kept ready to spill into the water. Other Memories replayed that agonized, twisting death which produced the spice poison to ignite a Fremen orgy.

A low arch framed more darkness on the far side of the basin. She could see the spillway there where water had been brought down from a windtrap. There would be more catchbasins back there, an entire complex of them designed to hold a wealth of moisture for an ancient tribe. She knew the name of this place now.

"Sietch Tabr," Odrade whispered.

The words ignited a flood of useful memories. This had been Stilgar's place in the time of Muad'dib. Why did that worm bring us to Sietch Tabr?

A worm took Sheeana to the City of Keen. That others might know of her? Then what was there to know here? Were there people back there in that darkness? Odrade sensed no indications of life in that direction.

Her Sister at the opening interrupted these thoughts. "We've had to ask for the rope to be brought from Dar-es-Balat! The people at the museum say this is probably Sietch Tabr! They thought it had been destroyed!"