Andrei's lamp gave out when they were halfway down the corridor.

  He stopped, Vlada a hot weight in his arms, blinking in aggravation at the swimming spots in his vision.

  Kori's hand found his elbow. "áida éla."

  He followed her touch and the sound of her clicking slippers and the scent, he fancied, of her hair.

  She turned, and he put out a hand to catch the frame of the door and swing around it.

  "I need to—" He began, but winced at Kori's imperious double-clap. The sound bounced off an ordered array of flat objects—cots—stretching to the walls. One cot was higher and softer-sounding than the others, and two other soft things stood on either side of it. Priests watching the concussed Brother Murad. Or, not watching, exactly, but doing whatever it was Andrei was doing.

  He took a confident step toward the nearest empty cot and cracked his knee against something.

  "Devil take it!"

  "éla," said Kori again, and in French, "You must learn how to step. Put her here."

  Her hands guided his.

  "Thank you." His knee still throbbed.

  "And now, Doctor?"

  Andrei's chin jerked up. But that voice had been one of the other priests, speaking Russian.

  "Care and treatment," he answered. "You there, has the patient vomited?"

  "No, My—no, Doctor."

  "All right. That's his biggest danger. That or he tries to get up and falls off his cot and bangs his head again. Your job is to prevent that. Hold him down gently, and it would be best if he lay on his side. Does his skin feel clammy?"

  "Uh?"

  "Cold, damp. Like clay."

  "Yes, Doctor."

  "So put a blanket on him."

  The other priest said something in Bulgarian. Something about hot water.

  "No, but we have cold water, too, don't we? A cold compress on his forehead might keep the swelling down. Yes. See to it."

  Slippers tapped as one of the priests moved in the darkness and Andrei turned his mind to his other patient.

  "A cold compress for the girl, as well. Bring her temperature down. Where the devil is Nikolai with the herbs? When I don't want him he's looming over my shoulder grinning at me, but when I want the madman he's nowhere to be found."

  The priests stopped clicking.

  "Don't call him that," said Kori. "Elder Brother Nikolai's loyalty is absolute." Her voice softened. "He's been testing you."

  "Oh, that was a test, was it? What a relief," said Andrei. "I thought it was a plot to have me killed."

  "And you slipped away from the dagger," said Kori. "Very good."

  The other priest, the one who spoke Bulgarian, cleared his throat and said something about stocks of grass.

  "The infirmary has its own stock of herbs," Kori translated.

  "Excellent," said Andrei. "Show me."

  She clicked her tongue. Andrei looked into the darkness and massaged his knee.

  "Does this stock include fuel for my lamp, maybe? Or, one moment. There's a calcium light in this infirmary, isn't there? Nikolai was taunting me about it. Why don't we make use of that?"

  The tale has been illicitly lifted; should you spot it on Amazon, report the violation.

  A pair of in-drawn breaths from the recesses of the chamber.

  "Yes," said Kori. "I have been curious about it."

  "What about unholy illumination and the like?"

  "This is an infirmary. Doctors need to see. Why do you think Nikolai ordered that calcium light and had it installed here?"

  "Nikolai ordered it?" asked Andrei.

  "From Berlin. He has many modern ideas."

  "Could have fooled me."

  The first priest said something in Good and Kori responded. "How many people do you need to help you care for Vlada and Brother Murad?" she asked in French.

  Andrei listened to the patients breathe. "I could do it by myself."

  Kori spoke to the priests again. Her tone of voice was light, but she received a humble chorus of "Yes, My Maiden."

  "They will depart and leave the care of the patients to you," she said.

  Andrei glanced at Kori, or at least he turned his face in the direction of her voice. Did she want to speak to him alone? "In that case, my dear, I will have to rely on your cave powers to activate the light."

  Kori snorted. "Cave powers." But she clicked her tongue and strode confidently across the room. Andrei could feel the breeze of her passage. "Follow me. Come to my voice, Andrei."

  "I am." Andrei groped around the edge of Vlada's cot and held out his hands toward where he thought the next one would be. It wasn't there. He found it with his other knee.

  "God damn it!"

  "Sht! You'll wake them. Click your tongue, Doctor Voropayevski. Give the walls a voice."

  Andrei clicked. "I guess cave powers take time to develop."

  "Here. Step closer. There's nothing in front of you but air."

  Warm fingers caught Andrei's reaching hand. Her palm pressed against his.

  Andrei froze. For a blink, he saw her. A green-purple woman flashed against the blackness.

  "Can't you sense it?"

  "Nothing but you," he said.

  Could he see her blush? Feel her hand grow warm against his? Andrei thought he could. Or maybe only wished he could.

  "Here." Kori guided Andrei's hand down and forward. He touched cold, oily metal. A nozzle, a valve, another nozzle.

  "Those are the oxygen and hydrogen lines." Kori gave him a small squeeze, delicious as a strawberry. "Feel this cloth tied around the hydrogen? The armature that holds the quicklime is here. Feel it?"

  "It feels like chalk."

  "It was before we fired it. Here, lick your finger and press it to the lime."

  Andrei froze, thinking about the licking of fingers.

  "What's wrong?" she asked. "Surely even you can find your own mouth with your hand." Her fingers withdrew before he could grab and kiss them, so Andrei had no choice but to wet the tip of his own finger. He brought it back to where he thought he remembered the quicklime to be and, after a bit of searching, found it. When the water on his finger touched it, the quicklime fizzed.

  "Feel that? 'Sin,' ái vu kálit. The burning stone. Now, find the spark lever. It works the same way as the one on your lamp. Open the valves, make the spark, close your eyes, and rotate the quicklime into position."

  "You remind me of my medical textbook. Very orderly. Very different from the real thing." Andrei found the valves.

  "Fiddling around with hydrogen and sparks in the pitch black," he said. "Why don't you just use candles?"

  "Smoke is very dangerous," answered Kori. "Even with Nikolai's ventilation improvements, a fire could eat up the oxygen in a room or fill your lungs with its smoke. Even if you remain conscious, you will be horribly vulnerable."

  "To whom?"

  "Not vulnerable to people. We all trust each other here. I mean the purity of your mind would be vulnerable. In French we say "one's judgment is clouded,' but in Good we say 'one holds his smoke.'" Ssa?dza sin dimín. Will you light the calcium, doctor?"

  "Wait." Andrei listened, but heard only four sets of lungs working. The other priests had let themselves out, as Kori had planned.

  Andrei lowered his face toward where he thought hers might be. "Mademoiselle." He dropped his voice to a whisper. Less than a whisper. He barely let his breath escape. The words were little more than a movement of his lips in the dark. "Kori. You trust me, don't you?"

  "That's a foolish question to ask." He imagined her profile, dramatic brows lowered in warning.

  "I have a plan." He barely let his breath escape. The words were little more than a movement of his lips in the dark. "Come with—"

  Her palm mashed against his mouth. It wasn't a slap, because a slap would have made noise. This was more like being smothered.

  They stood that way. Her palm against his lips. He could almost see her arm, glowing.

  "Be careful what you say." Kori spoke clearly, as if to tell him that there was no tone of voice low enough that some cave-trained ear wouldn't be able to hear it.

  "Oh," he said. "I suppose the walls have ears."

  "In the the Good Language we say 'the darkness knows itself. Tamssáta vu kness."

  Andrei felt like an idiot. But if they couldn't talk frankly—if such talk was never possible under this horrible mountain—then, what game was Kori playing by coming here?

  "Little Vlada was sleepwalking," she said. "It's common under the Mountain."

  Andrei examined the spot in the darkness where he thought Kori was. Was she lying? Telling a story for the benefit of their unseen audience?

  Even now, she could be planning to betray him. The prophetess could be handing him enough rope to hang himself, or leading him through some sadistic Thracian ritual, or any of a dozen other evil plots.

  "She came to you by herself with no outside interference?" he asked.

  "I didn't say that. She walked in her sleep, I said, with her dreaming mind open. The darkness knows itself."

  In that case, either the god of death was real and interested in Andrei personally, or else his life had been saved by sheer dumb luck. Or she was lying. Which answer would he prefer?

  "The lie."

  He started. It was as if Kori had echoed his thoughts.

  "Drokáss ésta maí dibráta va?ra," she said, voice as rich as black soil in spring. "The lie is the deepest truth. Now, find the lever, Doctor, and pull it."

  Andrei found, then lost, then found the lever again. He pulled it and was rewarded by a hiss and a dim, blue flame. After the utter darkness, that flame was welcome enough, but it wouldn't do much to help his doctoring. He still couldn't make out Kori's expression.

  "Close your eyes, I said!"

  Ah. She was impatient.

  The quicklime looked like a wedge of cracked chalk screwed into a little clamp on a rotating arm. Andrei slitted his eyes and rotated it into the flame from the oxy-hydrogen torch.

  The insides of his eyelids turned red.