She reached into her bag and retrieved a propane lantern. She flipped a switch and a small flame flickered to life. It didn’t seem like much, but as she positioned herself through the shaft, that little flame illuminated the darkness more brightly than I’d have guessed. Then she was gone, and a moment later her footsteps hit hard-packed earth with a dry thud and rustling of the sacks. I peered over the edge, deep into the shaft. Rebekah smiled up at me, holding the lantern over her head so that the glow turned her caramel skin to gold.

“I’ll go next,” Stone offered. He dropped his pack through the hole and followed it.

“Go,” Will told me. “I’ll close the hatch behind us and watch the rear.”

“Or stare at it,” I teased.

He licked his lips and they pulled into a little sideways grin. Smiling up at him, I eased my body through the hole until my legs dangled in clear air and all I needed to do was to let go. He gave me a reassuring look and I let my body fall. My senses quickened as I dropped and landed on my feet with grace and effortlessness. I stepped out of the way for Will to follow me and strained to see where Ethan and Rebekah had gone. They were talking just ahead of Will and me, lit by the glow of their lanterns. To my amazement, the tunnel had been carved out of solid rock. The air down here was cooler and less dry, and frankly it was more pleasant than aboveground. I picked up my pack and turned on my lantern. I started to get the second out for Will, but he put a hand on my arm.

“Save it,” he said. “I don’t need one to see. Three are enough.”

“Show off,” I grumbled.

“The passages open up into hidden locations all over the Citadel,” Rebekah called to us from ahead. We walked a little faster to catch up. “I’ve found four that lead out into the city, but this one travels the farthest so far. on one of my explorations, I made the discovery of a lifetime: an ancient underground city between Ain Dara and Aleppo, much like the city of Derinkuyu, north of here in Cappadocia—now modern Turkey—which was once the homeland for the Hittite civilization. The Hittites seemed to have taken a preexisting city built by an unknown civilization and made it their home. I believe they have done the same with the city I’m taking you to today. I am itching to reveal the city, but not until I know what’s beyond the door in the Sanctum. That’s why I rang in Ethan.”

“Door?” I asked.

“An enormous one, twenty feet high, and made of solid basalt,” she replied. “There are engravings in a language I’d never seen before and reliefs of creatures I believed at first were cherubim, but upon closer inspection, were creatures I haven’t seen in any Mesopotamian structure, or anywhere else in the world. The written language cut into the stone is far more complex than any language within thousands of years of its dating. It is almost alien.”

“The language is Enochian,” Stone explained, glancing back at us, the firelight dancing on his face and making him look a little younger. “The angelic language. It was no astonishment that Rebekah didn’t recognize it.”

“You can read it?” I asked, surprised.

“Again,” he said, “I like knowing things.”

My gaze fell to the tunnel floor. “I don’t quite remember it. I didn’t think anyone knew it anymore.”

“You may again very soon.”

This time Rebekah was the one who glanced back. “Remember it? You’re a little young to be a linguist.”

Ethan Stone gave an uncomfortable cough. I hadn’t realized until now how poorly informed this archaeologist was about what was happening out there. I’d need to be careful about what I said from now on.

“Who are you again?” she asked, growing a little suspicious. “You also seem a little young to be a university student. Will, I can see it, though he doesn’t look the type. A little brawny, he is. You’re both quite curious.”

“We’re what he says.” I wasn’t sure how to explain myself, so I kept my mouth shut. The only reason Rebekah had even joined us was to help navigate this maze of tunnels since she knew it best. We continued for miles, for so long I began to sing songs in my head to pass the time. The passages branched off randomly and we took a couple of turns here and there. The floor rose and fell, and sometimes the tunnel grew wider or more narrow. We passed a few places where the ceiling had partially collapsed, forcing us to climb over fallen rock and debris. Every once in a while, we passed statues of sphinxes and even one of a winged man who had to be an angel. We must have been getting close.

A heavy rumble shook the tunnel walls and floor, and dust sprang free in thick clouds. Rebekah gasped and Ethan swore. Will remained silent and closed the distance between him and me.

“A cave-in?” I asked fearfully as I pushed my hands into the wall to catch my balance.

Stone frowned, studied the ceiling. “That didn’t feel like a cave-in.”

“Nor did it sound like one,” Dr. Massi added.

I spun around to Will, who looked right at me. “Reaper.”

A small noise of confusion escaped from me as I stared past him and into the blackness. I laid a hand on his arm, instinctively drawing my body closer to his. “Will?”

“It’s not behind us,” he said in a low voice. “It’s up ahead.”

I whirled the other way and looked past the two humans with us. There wasn’t much room down here to fight and to protect our companions, but neither was there an escape route for the four of us. “Ethan, Rebekah,” I said. “Get behind us.”