"That's not light," she shouted into the comm, trying to scrabble backwards along the mirror-bright floor. The lead edge of the radiance was almost touching her flailing boots. Her finger twitched on the firing bead of the Sif. "It's something else!"

Hummingbird's answer was drowned out by a sharp blast. The shockgun rocked against her shoulder as a canister burst from the muzzle. Gretchen oofed and the recoil flung her down the hallway, legs and arms windmilling. She slammed into Hummingbird and they both flew back through the slanted doorway into the outer chamber. Behind them, a high-pitched z-z-zing ended in a blast of flame and light. Out of the corner of her eye Gretchen caught sight of the gray radiance rippling and twisting like a torn blanket in the strobe-light eruption of a hundred and sixteen individually packaged munitions.

In a cloud of dust, Anderssen untangled herself from the nauallis, hands working the reloading mechanism. Gretchen felt the heavy, solid thunk of a new canister levering into the firing chamber. Hummingbird scrambled up from the spreading dust as well, half-blinded by his disordered kaffiyeh.

"Clever," he barked sarcastically over a comm channel hissing with static and the same kind of high warbling wail Gretchen had heard in the cave on Mount Prion. "You must have done well in physics… Ai! Run!"

Gretchen was still raising the shockgun to cover the tunnel entrance when the nauallis bolted for the archway leading into the canyon. A shout of dismay strangled in her throat as the radiance boiled out of the passage. She caught a brief, fragmentary glimpse of a cloud of rock chips, bits of metal and what seemed to be frozen flame suspended within the advancing gray.

"Crap!" Gretchen sprinted for the doorway and leaped through the opening, hands protecting her head. The roar of static in her earbug was deafening and she slapped the comm off. Both feet hit the dust, sending up twin plumes of heavy yellow. Staggering, Gretchen ran across the bowl and scrambled up the tilted slab on the far side.

In the darkness, she lost sight of Hummingbird among a jerking, disorienting blur of canyon walls and sandy cavities among glassy-smooth boulders. Damning his cowardly name, she slid across another slab and dropped down onto a wide, gravel-strewn moraine. Wheezing for breath, Gretchen jogged up the slope and at the top she turned, nervous hands checking her belt, the sling of the shockgun, her rebreather – all the tools she needed to survive. A cough died in her throat.

The radiance had spilled out into the canyon bottom. Now, from a distance, the thing looked nothing like any light or illumination she'd ever seen. Strikingly, there were no shadows or reflections cast by the color. Instead, the already dark canyon dimmed as the shape grew among the boulders and flooded from the doorway. Gretchen adjusted her goggles, but there was no change save in infrared, where she hissed in surprise to see the edges of the formless gray merging with the subzero night while bright points of heat blazed in the center of the mass. But even those sparks were dying as she watched.

"Oh, no," she whispered, backing up. The Sif was in her hands again, but Anderssen realized with a grim certainty the gun was useless. The fading heat sources were the still-exploding flechettes she'd fired into the color, being avidly consumed by this…this…"What is this thing? Hummingbird!"

There was no answer on the dead comm. Gretchen turned and ran as fast as she dared, scrambling past rounded anthracite boulders and slogging through deep drifts of sand and dust. A hundred heartbeats passed and suddenly, as she dodged between two menhirlike stones, a pair of powerful hands seized Gretchen and swung her aside, into a pocket of shadow in the greater darkness. She yelped, swinging the stock of the Sif around in a sharp blow to the unseen figure's head. The honeycombed plastic thudded into something solid. A glowbean flared to life and Gretchen found herself facing a wincing Hummingbird.

"Where…" Anderssen tried turning her comm back on. "…have you been? What is that thing in the canyon?"

"A hungry dream," Hummingbird said, though the staccato warble and keening in the background of the channel nearly drowned him out. "Or rather, what a current at the edge of the valkar's dream made in this waking world."

"A dream?" Gretchen fought against a fierce desire to smash the butt of the shockgun repeatedly into the man's face until he made sense. "Dreams don't have form, idiot bird! They don't eat up explosive munitions like toasted maize and come looking for more!"

Hummingbird pushed the muzzle of the Sif away from his face with a fingertip. "Even dreaming, the valkar distorts the world with the weight of its presence. Even these dead stones retain some memory of a once-living world." He slapped a gloved hand against the glossy obsidian rising up above them. "Nothing survived the devastation intact. But you saw the effect Russovsky's stone had on the organism in the cave – even the pattern memory of an often-used artifact could stir the formless to take shape. This world is rife with parched, formless memories."

Hummingbird stopped, tensing. Gretchen turned, hefting the Sif onto her shoulder, muzzle down. Gun useless, she thought with very faint amusement. Make a note for Bandao. Good for feeding colorless light.

"I was very foolish to come here – Hsst! Something is coming."

Outside their tiny shelter, the gloom in the canyon – barely disturbed by the thin ribbon of brilliant, unwinking stars high above – deepened. Gretchen fought down a desire to bolt from their meager shelter. Hummingbird's fist closed on her shoulder in painful counterpoint to the static roaring in her earbug.

The color was there suddenly, gliding out from behind a house-sized boulder. Again the gray radiance did not extend beyond an indistinct, wavering shape. Gretchen's eyes widened, taking in a burning-hot point drifting within something like a bifurcated cone with a forest of tentacular legs moving restlessly beneath. She focused her goggles on the hot centerpoint and saw a flechette tumbling in place, hissing and spitting slow fire. The metallic sheathing was rapidly disintegrating. Apparently unaware of them, the color drifted past, a gray cutout against a flat velvet background.

Hummingbird's fingers clasped her wrist and the comm channel fell silent. He leaned close, pressing his mask against hers. "We have to get away from here or we'll be fuel too."

Nodding, Gretchen peered out around the corner, saw nothing – no wavering, indeterminate blotches of lightless color – and slipped out, weaving her way through the debris scattered at the mouth of the canyon. Hummingbird was right behind her.

Heedless of what might see them – if the color had eyes or something passing for an organ of sight – they ran up the broad, open slope flanking the entrance to the slot. Anderssen immediately started wheezing again. Her leg muscles sparked with pain and she nearly collapsed at the top of the ridge. Hummingbird caught her arm, dragging Gretchen to her feet.

"Run," he barked, voice a barely audible squeak in the thin air. "Don't -"

Gretchen looked back, trying to catch her breath.

Amorphous gray shapes were emerging from the mouth of the canyon. Not all were cone-shaped – some shifted and distorted in the brief moment of her glance – and others strode swiftly on long, stalklike legs. A sensation of hostile desire struck Gretchen like a physical blow, though at such a distance there should have been no way for her to ascertain expression or intent.

She turned and ran, head down, forcing cramping legs and thighs to bound across rocky, uneven ground. Hummingbird loped at her side, keeping pace, though Gretchen guessed the old man could easily leave her behind.