"Hu–Hu–" Gretchen couldn't make her voice work, the word coming out a choked squeak. Though gripped by a terrible desire to flee, Anderssen crept inside, shoulder to the right-hand wall as she scuttled towards him. "Hummingbird!"

"Look at this," the nauallis said calmly, pointing with the wand at a smudge on the smooth stone. "Remains of a glowbean, I think. Russovsky must have…What is it?"

Gretchen was clutching his arm, the rasp of her breathing loud in her ears. "Look at the floor, at the doorways," she hissed, pointing with the barrel of the Sif. "They're level."

Hummingbird nodded, though he tensed as well. "And so?"

"This is a First Sun building," Gretchen said in a tight, controlled voice. "This postdates the release of the eaters, the destruction of the surface, the rise of the Escarpment, everything. Your valkar made this place."

There was a hiss-hiss on the comm circuit. "I don't think so," Hummingbird said after a pause. "Look at this wall. This is not worked stone, not planed or cut or burned with a tunneller. The doorways are the same."

Gretchen peered at the wall, finding concentration and focus elusive amid the rampage of adrenaline coursing through her. "I…I suppose…" Then something odd about the surface caught her attention and she dialed up the magnification on her goggles. "Hmm. That's very strange – this surface is solid."

"Yes." Hummingbird moved along the wall to the inner doorway. Cautiously, he looked around the corner, then drew back. "Almost perfect, I would hazard."

Keeping the muzzle of the Sif pointed away from the Mйxica, Gretchen sidled up to join him. "Real stone isn't so smooth," she muttered under her breath, suspiciously checking the exit to the canyon. "It's usually porous, even a fine marble or granite. Filled with minute hollows, concavities…"

"True." Hummingbird looked around the corner again, leading with his lightwand. "But this is not stone as you think of stone. This is a wall assembled an atom at a time over a million years. Almost perfectly solid and more than a meter deep." He slipped into a corridor with walls slanting inward to a flat ceiling over a dusty floor.

Gretchen darted across the opening and swung the Sif to cover the passage. The tunnel reached back to end in an angled wall. Hummingbird moved carefully, one gloved hand pressed against the slanting wall.

"Watch out for this floor," he said, voice a low buzz in her earbug. "Like the walls, it is dangerously slick. There is very little traction."

Gretchen looked down at the dusty surface. A mirror image of her cloak, mask and rebreather stared back through a gray film. "Okay," she said, testing the surface with her boot. Sliding her foot from side to side elicited a queasy feeling like slipping on new ice. Pressing directly down seemed to gain some purchase. Ahead of her, Hummingbird was moving very slowly, taking his time and placing each foot with careful precision. Gretchen followed with equal care, keeping to the opposite wall.

The sloped passage turned to enter a second chamber at an angle. Hummingbird paused just outside the junction, risking a quick look inside before beckoning for Anderssen to join him. Gretchen moved gingerly to his side – her boots kept wanting to slip out from under her – hands grimly tight on the handle and stock of the Sif.

This room seemed to have no ceiling – or none she could see – and three smooth walls. The fourth, opposite them, was rough and unfinished. Gretchen's mouth tightened, making out irregular markings on the wall – inset spirals, whorls of raised, grooved rock – and she hissed in warning. At the base of the wall were scattered a number of cylinders.

"There." She pointed, indicating a section of bare stone which had been broken open. Hand-sized rocks lay in an untidy pile at the foot of the wall. Boot prints scuffed an ancient layer of dust. "Russovsky took the embedded cylinder away."

Without waiting for Hummingbird to respond, overcome by her own curiosity, Gretchen walked stiffly across the floor to the nearest cylinder. The artifact seemed much the same as the one Clarkson had cut open on the ship – a third of a meter long, four or five centimeters across – and the exterior was encrusted with the same kind of lime-scaling. Very gently, Anderssen nudged the device with the muzzle of the Sif, making the thing skitter across the impeccably smooth floor. The cylinder did not burst open.

She could feel Hummingbird's tension from the doorway, but Gretchen ignored him for the moment, moving to the cavity broken in the stone. Up close, she saw the wall was raw irregular rock, rising up through the floor at an angle and vanishing into impenetrable darkness overhead. The entire surface was crowded with fossils – more of the anemonelike structures, the fluted curl of something like a snail, serrated ridges indicating a swimmer with multiple spines. A flattened, bifurcated cone. Scorch-marks surrounded the ragged opening where small blasting charges had been used to split open the limestone.

"What made this place?" Gretchen whispered into her throat mike as she leaned close to examine the surface of the ancient sediment. She could see hundreds of specimens within arm's reach – a glorious view into a lost, dead world. "Did something survive after the valkar fled into hiding?"

"Ghosts." Hummingbird hesitated, remaining crouched in the entranceway. "You've seen what lived – the microflora – but they did not make this shrine. This is memory made solid."

"How?" Anderssen backed away from the wall, swinging the gun to cover the rest of the room. "You mean like Russovsky?"

Hummingbird waved for her to get behind him once she reached the archway. "I have not seen this before myself," he said in a low voice, "but the pyramid contains references to such things. The valkar is dreaming, but it is not powerless. A subtle influence extends throughout this world, power seeping from the hidden heart. Even when the crust was shattered and remade, not all memories of what lived here before died." He began to back up into the hallway. Nervous, Gretchen followed.

A white frost began to form on her breather mask, which was worrying. The night air of Ephesus was far below freezing, but the respirator should be trapping the water vapor in her breath. Only CO₂ should be escaping. "Crow, something's happening…it's getting very, very cold."

Hummingbird turned up the intensity of his wand and raised the light high. Shadows fled away down the passage.

"There's something here," the nauallis hissed in alarm, staring intently around at the glassy walls. Gretchen tried to hurry, but the glassy floor immediately betrayed her. One foot flew out and she crashed down hard on her right hip. A gasp of pain burst from her throat. The barrel of the Sif banged on the floor and the weapon flew from her fingers. The nauallis flinched, but kept up his steady, careful pace toward the outer room.

"Anderssen, quit playing about and get up," he hissed.

Gretchen tried to rise, but her hands slipped on the mirrored floor and she spun helplessly. One boot hit the wall and skittered away. Even as she groped for some kind of purchase, she saw a spreading reflection of grayish light spill across the slanted wall. The butt of the Sif hit her head. Gretchen twisted into a roll and flopped over onto her stomach. Grasping fingers closed around the weapon and her boot struck the wall square enough to stop abruptly. She looked up.

Hummingbird had backed past her in his flat-footed crouch. The little gun was pointing into the strange gray light, absurdly dwarfed by the bulk of his gloved hands. Gretchen twisted her head around and her eyes went wide. Reflex twitched the Sif into aiming position.

The passage was filling with a steady gray radiance. An indeterminate crepuscular color shone from the air. The doorway to the room of the sea had vanished in the endlessly repeating reflections of the mirrored walls, floor and ceiling. Where the gray existed, there was nothing else – no shadow, no stone, no edges or divisions. Gretchen realized, with a chill start, the light was moving rapidly toward her, spilling along the passage in a colorless tide.