"Last night…" she started to describe what she'd seen, but then changed her mind. "I would feel stupid about running," Gretchen said, glaring at the old Mйxica, "but you were running too. So what did come out of the cave? Were we ever in any danger?"

"We were," Hummingbird replied. He seemed tired, too. "Even at the end, when they had no more substance than a shadow, we were still in danger. I thought…" He stopped, considering his words. "When you ran, I feared things would go badly for you. I am glad they did not. We were lucky."

"We were idiots – I was an idiot," Gretchen said in a very sharp tone. "They ate the energy released by the Sif bullets, didn't they? If I hadn't done that, we'd have been able to walk right out."

"You did not know what would happen. I did not know either." Hummingbird made a dismissive gesture. "And I wonder if they did eat the bullets from your gun. I'm not sure they had the strength to do so. We might have seen only an echo of what the substance experienced. A living, moving memory."

"I saw a flechette in one, hanging in the air, as if the explosion itself had slowed down and was being consumed!"

"I wonder…" Hummingbird raised an eyebrow wryly. "If we go into the tunnel and examine the rear wall, it may be we find the impact marks of each and every flechette – if the entire passage has not collapsed as a result of the explosions."

Gretchen's face screwed up in a disbelieving grimace. "Does this happen a lot with your sight?"

"Sometimes." Hummingbird's expression turned grim. "Achieving clarity does not mean you have learned to discern truth from falsehood. The world around us is filled with too much data. Why else would our infant minds learn to hide so much from our consciousness? Some students are blinded by the clarity they achieve." He raised two fingers. "This is the second obstacle a student must overcome: control of sight."

"How long," Gretchen said, rather suspiciously, "does that take?"

"Years." Hummingbird's voice was flat. His right hand twitched. "The drug I gave you…is a shortcut. But one usually given only to students who have passed the first obstacle."

"Which is?" Gretchen's lips drew tight and a dangerous glitter entered her eyes. What was in that packet? What did he do to me?

"The first obstacle is fear, Anderssen-tzin. It is to achieve clarity of mind before you attain clarity of sight." The nauallis shrugged. "I admit giving you the teonanacatl was a throw of the beans. I was hasty."

Gretchen swallowed, her throat dry with a bitter aftertaste, and she drank deep from one of the water bottles. Even the stale, metallic taste was preferable to the flat, oily fluid from her recycler. "You seem to be a very reckless man, Hummingbird-tzin. Are you well regarded by your fellows?"

The nauallis did not reply, his eyes becoming guarded again. Gretchen stood up and put her cup and spoon away, stowing them in the little cook kit from her rucksack. Nervously, she paced the perimeter of their shelter, listening to the storm wailing outside and peering through the filament at the Gagarin. Both Midge s seemed to be intact, though they were straining against the sand anchors like hounds against the leash. Finally, when the unsettled, churning feeling in her stomach had leveled off to a dull burn, she examined her hands in the dim, sulfurous light from outside.

Gloves. Fingers. They seemed entirely ordinary. Can I focus? How do I…

She concentrated, trying to discern the superlatively sharp level of detail she'd perceived before, where every grain and pore and wrinkle in the gloves came into view. Nothing happened. Her head started to hurt. Scowling, she pushed up her goggles and rubbed both eyes wearily. Stupid clarity…nevermind.

"What are we going to do about the tunnel and chambers?" Gretchen hugged herself, feeling cold despite the suit heaters. "Don't you have to 'clean it up' somehow?"

Hummingbird nodded slowly. He pointed at the entrance to the overhang. "In my Midge there are explosives, somewhat more powerful than your shockgun. When the daystorm clears, I will go into the tunnel and place them."

Gretchen laughed, unaccountably relieved to hear something so mundane and practical from the old man. "You're going to blow the place up? Now that does sound like the Empire at work!"

"Each tool," he said stiffly, "to a purpose. Those structures serve as a focus for this 'color' we saw. They allow something to take a shape where it should have none. So, I will destroy the entire location and hope – hope, mind you – the memories clinging to the stones and rocks themselves are scattered into oblivion."

"And the cylinders we saw in the inner room?" Gretchen clenched her fists tight against her sides. "You'll bury them under a million tons of rock?"

Hummingbird nodded slowly, watching Gretchen's face intently. "I will."

"What about Russovsky? What do you think happened to her?"

"She stumbled into part of a dream, someplace where a fragment of this sleeping power seized and consumed her. In that moment, she was taken over, into its context, rather than our own. Something came back out – the shape you saw in the first cave – like a ghost, perhaps curious, perhaps a reflex of her own memory. Even a shape retains memory of its past."

"The version of her on the ship was only an echo?" Gretchen tried not to lick her lips nervously. "Do you think she might have survived the experience? Maybe she woke up later and found her ultralight gone, taken by the copy?"

Hummingbird was nonplussed. His eyes narrowed in suspicion. "Have you seen something to indicate she survived?"

"I…no, no I haven't seen anything I could swear was real."

"But you saw Russovsky, or something which looked like her." The nauallis gave her a sharp look. "Last night? When the gray was upon you?"

"Afterward," she admitted. "When the gray – the visions – had passed. She helped me up. I felt her hand – a physical hand – in mine!"

"And then?" The nauallis rose and came to her side. His green eyes were tense and sharp. Gretchen could feel him looking at her. The sensation made her skin crawl and she backed away.

"Then – nothing. I was distracted for a second and when I looked back, she was gone. I looked all 'round, but…nothing. Vanished."

"An illusion?" Hummingbird sounded as if he were questioning himself. "The radiance of the gray grew stronger when the flechettes exploded – and then it weakened very quickly, as if being so strong, so solid, exhausted the energy. By the time it surrounded us, there was barely anything left."

Gretchen spread her hands. "Maybe. I have no idea, really. You're the one with the secret knowledge. But tell me this – you stopped, you sat down, you let the 'gray' wash over you. Why? What had you guessed about them?"

"I risked." The corners of the Mйxica's eyes crinkled up. "Such ephemeral things as these, they exist on a very narrow margin. They are parasites. They need to 'eat' with as little cost to themselves as possible. If there is a rich source of what they need, they will flock to it like bacteria growing in the outwash of a factory power plant." One hand moved to indicate the mountain above them. "This is not a rich paradise. This is a desert. Here we are food, not just our bodies, but the exhalation of our breath, the leakage from our recyclers, radiation from our power-packs. The explosion of the bullets from your gun."

Gretchen pressed a thumb against her left eyebrow. A too-familiar tickling was starting to brew behind her eye. Swallowing a trace of nausea, she punched a code on her medband. "So – you're saying our fear and panic were enough to keep them alive."

"Fear," Hummingbird said, giving her a piercing look, "is always the enemy."