Keep it down, Diana,” Dr. Reed said. “Crane’s people are all over here.”

I called up sharply through the ventilation shaft. “Diana. Hey, Diana. Dr. Reed. Hey. Can you hear me?”

But they didn’t hear me, and from their overhead rumblings, I knew they were about to pass by. I took out my Sikh blade and banged it against the inside of the shaft.

Bing … Bing … Bing … Bing …

It made a sound similar to the hammering sounds I’d heard in my sound-bending trance. Maybe what I had heard was those people communicating, using the sound of their swinging hammers to talk to one another across the underground city? Maybe, but I needed to communicate now. I wished I knew some Morse code.

I tapped louder, faster. It had to work. Come on, Diana, I thought, please listen.

Bing … Bing … Bing … Bing …

“Do you hear that, Mom? That weird ringing sound?”

Bing … Bing … Bing … Bing …

“I do hear something,” Dr. Reed said. “I can feel it in my legs, too. It’s coming from underground. How can that be?”

“I think we’re right on top of it,” Diana said.

“Diana! Dr. Reed!” I whispered sharply again. “Margaret!”

“Leo?” Diana said.

“Yes! It’s me. I’m down here. Way below ground. Follow the ringing sound.”

I kept tapping the kirpan, hearing their footsteps growing louder, until when I looked up, I saw Diana’s face filling the opening.

“Leo?!”

“You came!” I hollered. “Is your mom okay? I think Crane poisoned her.”

Diana’s face disappeared and was replaced by Dr. Reed’s.

“I’m fine,” she called down. “I’m fine now. I wasn’t, but I walked it off. But what are you doing down there, Leo?”

“I went to find the mask. And I found it. But I also discovered a whole underground city down here. Tunnels and tunnels. A whole labyrinth. And bones, too, ancient human bones.”

“What?”

“I think they’re skulls of really early humans. Is Hollis with you?”

“No, we haven’t seen him,” Dr. Reed said. “Did you say skulls? Not skull?”

“Yes, there’s hundreds of skeletons down here.”

“Hundreds?” she echoed in astonishment. “Why don’t you come out of there, then?”

“Listen, I lost my flashlight, and I think I broke my wrist. I’ve got the mask, but I’m not giving it to Crane. I can’t let him see me. Find Hollis, and I’ll figure out a way out of here. Do you see Crane?”

“You broke your wrist?” Dr. Reed gasped. Then she modulated her voice into a whisper. “Wait. He’s coming. Diana, stand up and move away. Pretend you were tying your shoe. We’ll find Hollis, Leo.”

Then Dr. Reed pulled her face away, and I heard them jogging away. I could hear some scuffling, then the faraway sound of Crane’s lizardy voice.

“Well, if it isn’t Diana and Dr. Reed,” I heard him say. “What are you doing out here, ladies? Come here to steal my prize, eh? Well I won’t let you. Meet your new best friends.”

“Hey, babe,” I heard Dmitri say, right above of me.

“Get off me!” Diana shrieked.

“Margaret, for the sake of my boys, I’ve given you a great deal of rope during this expedition,” Crane said. “Now, Klevko, tie them up.”

“No rope, boss.”

“Use your shoelaces, then, you donkey.”

“Get your hands off me!” Dr. Reed screamed.

I heard the sounds of a struggle, and Diana and her mother were led off. It took a minute for their cries and protests to stop, but they eventually did. My heart sank. I wouldn’t put it past Crane to abandon them or even hurt them. He’d already poisoned Dr. Reed. I had to get to the surface and help.

Tucking my dagger into my belt and slinging on my backpack, I tried to retrace my steps. With my eyes adjusted to the darkness, I saw that every fifty to a hundred feet or so, there was a ventilation shaft that let in the faint star- and moonlight. It was just enough light to see shapes and the slope of the ground. I jogged ahead in the darkness, kicking my foot along the ground searching for my gravel trail, and sliding my hand along the wall until it bumped into a few of those knobs I’d seen earlier. Perhaps, I thought, those knobs were like little rock drums. I tapped the kirpan blade against one of the knobs, and the sound it produced was entirely like those sounds I heard when I touched the mask and not too different from the chimes from the Byong Ku death dance. I tried one of the bigger knobs.

Each differently sized knob made a beautiful ringing sound, and each note bounced off the rock walls, back and forth. And though I can’t be certain, immediately after I’d tap a knob, I could see a brief flash of alexandrite color ricochet against the walls. And if I listened really deeply, I could almost feel the shape of the tunnels, like a type of radar. Between listening as deeply as I could to the reverberating tones and the faint light from the ventilation shafts, I had enough information to navigate. I could find my way out. I’m on my way, Diana.

I jogged uphill, tapping knobs and searching for starlight, and in almost no time, I picked up my gravel trail. It would lead me to the entrance. But Crane would be there. He’d be waiting. And he’d take the mask. I wasn’t going to give it to him. It wasn’t his, just like the other half. That wasn’t his, either. It was mine. It had been my father’s, and when he died, it became mine. Crane had stolen it from me, claimed it as his own, and when somehow, through a twist of fate, the mask had found its way back to its rightful owners, he’d stolen it again. That was his way.

But he wouldn’t get his way this time. I had to defeat him. But he was smart, and tough. Not even Mike Hazel could get the best of him, and I’d been watching Mike Hazel take down slumlords and New York conmen for years.

The solution was suddenly simple. I had to think like Crane. What would Crane do if he were in my position? Crane used lies, deception, and misdirection. And his most effective trick was to find what you really loved and take it away from you, use it as bait against you. Make it rotten. And what did Crane love? Money … but above all else, his beloved mother, Marie.

The secret password to my escape, my key to the surface.

I took out my H4n from my bag, the one I’d traded Trevor and Jeremy for. I turned it on and pressed record, the red light steady. I spent the next few minutes leaving Crane a personal message I was sure he’d love. Then I hurried to the entrance to the underground city, the chamber just after that tiny crevice of a corridor.

“Crane! Crane! Can you hear me, Crane?!”

I heard his voice a moment later, thin and hollow.

“Leo? Where have you been? We’re still working on the rope — Cyril jogged back to the village an hour —”

“Never mind the rope! I’ve been exploring and I’ve found a whole underground city down here. I’ve never seen anything like it. The farther down you go, the lighter it gets. You’ve got to get down here, now! Your mother, she was right about everything, Crane. Everything!”

His voice no longer sounded thin, but excited and intense.

“Tell me what you saw, Leo!”

“A path to the hollow Earth!” I said. “Boskops artifacts, amazing technology from the future. Just come down right now, Crane. It’s so dark you’re going to have to follow my voice. But the deeper you go, the lighter it gets — you won’t need a flashlight. I’m serious! I can’t believe it myself!”

“Did you say Boskops, Leo?”

“Yes. Just like your mother wrote. They were here.”

“I’m coming right now,” he panted. “Right away. And the mask? Did you find it?”

“It took me a while, but I got it. I’m holding it now, but forget the mask! This is the real deal down here. The discovery of the century, maybe of all time. Your mom got it all right. Everything. Come down now. Just follow my voice!”

“I’ll be right down. Klevko, you wait here for the rope. We’ll need it to pull me out. Don’t stray or I’ll have your hide. Okay, Leo, I’m heading down now!”

“Don’t worry,” I called. “The shaft will break your fall!”

I heard something big sliding down, then a hoarse groan.

“I’m on my way, Leo. I’m down. A bit rough, but no bother. No bother. No pain, no gain.”

“Just follow my voice, Crane,” I said, and continued saying things like that, egging him on, as I made my way into the underground city, through one labyrinth after another, until I came to a dead end. There I took out my H4n, turned up the volume all the way, and placed it in a small crevice near the ceiling. Then I pressed play, and set it to play an infinite loop.

“Follow my voice,” the H4n blared.

I dashed back the way I’d come, following the knobs and the starlight and kicking apart my gravel trail. I made it all the way to that first tunnel, where I’d taken the first fork to the left. This time I ran the opposite way and there I waited.

“I can barely squeeze through this tunnel. Leo? Where are the artifacts?”

“You’re almost there,” I said. “You have to be patient. Go left at the first fork. Just follow my voice. You’ll be there soon.”

“Oh my goodness,” Crane said, his voice really near me. “This is man-made. What treasures I’m going to find here.”

He felt his way down the tunnel.

“Oh my. Oh my. Mother, you did it, Mother. I knew you were right, Mother,” his voice rang out, and trailed off as Crane sprinted into the deep.

After he’d passed, I ran for the exit. When I got there, I looked up to see Klevko’s puffy face staring down at me.

“Where is the boss?” he called down to me.

“He’s heading to the room with all the treasures,” I said. “He wants you to come down with the bags so he can carry everything. Dmitri, too. There’s more than enough for everyone.”

“But how will we get back up?” Klevko said. “We still have no rope. Dmitri, he is small and strong, and perhaps he can climb through. But I am a large man.”

“Don’t worry about it, Klevko. I’ll get the rope from Cyril and we’ll pull you up. Come on, you’d better hurry. I can hear him yelling now. There’s a ton of gold and stuff down here.”

“One minute, Leo. I will just put on my jacket.”

I heard him whispering frantically to Dmitri in the same voice I’d heard in the Pomantong Cave.

“Put on your jacket like me,” he whispered. “It has pockets, so we can take many things for ourselves. He must not see.”

The grave robbers were at it again.

“I’m coming, Leo,” Klevko called. I looked up and saw his feet dangling above me. The shaft was narrow, and it was all he could do to wedge his big belly through it. He fell the last five feet on his padded behind. Dmitri followed him down, looking like he was ready to do business.

“Which way?” he asked.

“Straight ahead,” I said. “Turn left. You can’t miss it. Help me out before you leave.”

Klevko hoisted me up and I climbed on top of his massive shoulders. I saw an outcropping near the top that I thought I could use to pull myself to the surface. But with my broken hand, I didn’t think I could do it. The pain would be unbearable.

Then I thought of Diana and Dr. Reed, tied up somewhere outside. And Hollis … who even knew where he might be? I took a breath and put my broken hand on the ledge, and the good one on the rocks across from it. Then I pulled the entire weight of my body up. I pulled and screamed at the same time. The pain was indescribable — like an electric shock traveling through my body. But it was brief, and in a matter of seconds, my head was poking out of the crevice. The sky to the east was slightly blue. I scrambled with my feet to get some traction against the shaft wall, kicking Klevko in the head in the process. And then I was up, stomach on the ground, slithering away from the opening.

“Go,” I called down to Klevko and Dmitri. “I’ll wait here.”

I watched them take off down the labyrinth of tunnels, knowing that they were in for a wild goose chase.

Dr. Haga was there, staring at me. Mr. Singh was nowhere to be seen. Our villager guides were just watching. They didn’t seem to know about the secret crevice, and their eyes were wide in amazement.

“Dr. Haga, can you help me find something to cover this up?” I said, pointing to the crevice.

“If you cover it up, it will be difficult for those inside to find the opening,” he said.

“I know.”

He smiled. “We’ll use my jacket,” he said, laying it down over the crevice. “Would you like my shirt, too? My pants?”

“Nah,” I laughed, breathing deeply.

He said something to Kavi, and all of them burst into hysterics. Then they used their knives to slice up Crane’s bag, and splayed it over the hole, tucking dirt around it so no light could get in. The sky was getting lighter blue to the east, a hint of faint purple bleeding into the night.

Beneath the still unseen sun, I saw Dr. Reed and Diana sitting back to back on the ground, their hands tied together. They were blindfolded. I recognized the eye masks from the Sultan’s plane. Maybe Mr. Singh had taken a few extra.

I ran over to them, reaching them just as the first rays of the sun streaked down into the valley from behind the mountain.

“It’s me,” I said.

“Leo!” Diana cried.

“It’s okay, now,” I said, taking off their blindfolds. “You’re okay.”

I cut their shoelace binds with my kirpan, then hurled it away as far as I could throw with my left hand.

“I knew you could do it,” Diana gasped, bounding to her feet and throwing her arms around me. And she gave me a kiss on the cheek, then turned red and rushed over to her mom to help her up.

“Sorry,” Diana said, embarrassed her mom had seen everything.

“That’s all right, honey,” Dr. Reed said as she rubbed her wrists. “I believe anyone who finds his way out of the labyrinth and saves the girl deserves a little bit of love for his heroism.”

“Are you guys okay?” I said, blushing. “Did he hurt you?”

“We’re just fine, Leo,” Dr. Reed said. “But what about you? Let me see that hand.”

She reached out, but I recoiled, holding it against my chest.

“Don’t touch it,” I snapped. “I’m sorry, it just hurts a little. I have to find Hollis now.”

“Hollis is back at the village,” Diana said. “Aru found him and took him back. He was scared.”

“But how did you know where to find me?” I asked Dr. Reed.

“It helps when you speak the language,” she said. “I figured you were all heading to the Land of the Dead, and Diana here has learned a thing or two about tracking from her time in Borneo. So I guess it hasn’t all been a waste, huh, sweetie?”

“Can we see Hollis now?” I asked. I needed to see him with my own eyes, to know for sure that he was unharmed.

Diana and I ran all the way there — with Dr. Reed, Dr. Haga, and the villagers following behind. On the way, we met Cyril, who was returning with the rope. Dr. Haga said something to him in their language, and Cyril just nodded and turned to follow us, bringing the rope back with him.

When we got to the village, we found Hollis sitting on the steps of the longhouse, playing a song on a nose flute with Aru and some of the village elders gathered around him. The chief was there, too, and the amazing thing was, he was singing along as Hollis played. Not in any kind of tone we might recognize. It sounded almost like those hollow chimes I had heard in my visions or on the knobs from the Land of the Dead. It wasn’t Mozart or anything, but it was definitely a melody. When he saw us, he stopped singing and spoke to Dr. Reed. She smiled at him, nodded, and turned to Hollis and me.

“Laki Jau says the sons of Kirk have shown him the music,” she said. “Perhaps now he can sing his ancestral songs. He thanks you.”

I loosened the straps of my backpack and approached the chief.

“This is for you,” I said. “I brought it back from the Land of the Dead, to replace the one my uncle has stolen from you.”

I bowed and laid the backpack down at his feet. Laki Jau took it and held it up, turning it around in his hands. He didn’t know what to do with it, so Hollis reached over and helped him unzip the pouch. Then he reached inside and pulled out the mask.

“You found it!” Hollis cried. “Way to go, Leo.”

When Laki Jau saw the mask, he gasped. Turning it over and over in his hands, he ran his fingers over the face, touching it like the sacred object it was. He didn’t linger over the diamonds and gold — they seemed no more interesting to him than the batlike ears or the carved wood.

All the villagers had gathered around by now, and he held the mask up for them to see. Dr. Haga, who had been watching the chief from his position behind me, stepped forward. From out of his backpack, he produced a leather pouch with the initials CR embroidered in red silk thread.

“Your uncle gave this to me for safekeeping,” he said to me.

Then he walked up to the chief and handed the pouch to him.

“If you would, Dr. Reed, please tell the chief this is from me, with apologies for bringing Crane Rathbone to disturb the harmony of his village,” he said.

The chief looked at the leather pouch and touched the soft calfskin.

“Here, let me help you with that,” Hollis said, again reaching out to unzip it so the chief could see what was inside. Hollis held the pouch open for the chief, who reached inside and pulled out the other half of the Siamese twin mask, the one Crane had stolen from them. Dr. Haga looked over at me and smiled.

“The circle is complete,” he said simply.

The chief picked up the familiar mask in his free hand. It was more faded than its twin half, but in all other respects, it was completely identical. The jagged edges where the masks had once been connected seemed to match perfectly.

Laki Jau rose and held both masks over his head in the morning sun. As if drawn by a magnetic force, the two halves of the mask fused together in a perfect fit. When the chief saw this, he let out a high-pitched scream that echoed through the village. He held the conjoined masks and sang some words, in a halting and unpracticed melody.

“What’s he saying?” I asked Dr. Reed.

“He says that now at last Laki Tenangan and Doh Tenangan are reunited. The twin gods can rule together, and all will be good for our people. The sons of Kirk have brought peace to our village.”

The chief walked over to me and held the mask out. The eyes, all four of them, no longer seemed hollow and dark but hopeful and full of promise. I reached out and touched the sacred object, and heard its song in my secret ears — the lapping waves, the beautiful chimes, the birdsongs of Borneo. And underneath it all, I heard my father’s voice repeating my name.

“Sound Bender, Sound Bender,” he called.

Yes, Dad, I thought. I’m here.