"Tell me," I said. "Whatever it said. Tell me."
Marcus tried. I watched him try.
His mouth opened. His throat worked. His lips shaped the first word, and then the second, and nothing came out. No whisper, no breath, nothing. He grabbed his own neck with both hands, eyes bulging, and made a sound like a door scraping on a dry hinge.
"Stop," Cassian said, and caught his wrist. "Stop. You will hurt yourself."
Marcus gasped and bent over, coughing. When he straightened, the words came back, ragged and normal. "It's like someone put a hand over my mouth. I know what it said. I can hear it. I just can't—" He swallowed. "Every time I try, it's gone."
"It guards its words," Cassian said grimly. "Hollows take voices first. That is why."
"So it's using his own mark as a gag," I said.
"Yes. Until the Hollow is dead or the mark is broken, whatever it told him stays buried." Cassian's eyes hardened. "It wanted us to know there is a secret. It wanted us to wonder. That is the oldest trick it has."
It is working, said the voice in my head, dryly.
You're not helping.
I am being honest.
I looked at Marcus, at the black lines creeping past his elbow now, and made my decision.
"Then we kill it first," I said. "Tonight."
"We do not know where it is."
"I do." I hadn't known I did until the words were out of my mouth. "Or I think I do."
It came back to me in pieces, the way a dream does when you stop chasing it.
I sat on the dusty floor of the clock tower with my eyes shut and my hands pressed against my knees, and Cassian crouched in front of me, speaking low.
"Do not reach for the memory. Listen for it. The blood remembers what you cannot."
So I listened.
At first there was only the city: traffic, a distant siren, pigeons in the rafters, forty thousand heartbeats scattered like stars across a dark field. Then, underneath all of it, I heard something else. A hush. A shape of quiet, like a hole cut into a sheet of noise.
"There," I whispered. "East. A long way east. Something that doesn't beat."
"Good," said Cassian softly. "Now follow it backward."
The quiet pulled at me. And suddenly I was standing in a corridor with peeling green paint and flickering emergency lights, bare feet on cold tile, the red moon blazing through a hole in the ceiling. I was walking. I was sleepwalking. Something was calling my name, over and over, and I was answering it.
My eyes snapped open.
"Saint Mercy," I said. "The old hospital on Delancey. They shut it down when I was ten."
Marcus stared. "That's like six miles from your apartment."
"I walked there," I said. "That night. In my sleep."
Yes, said the voice, so quietly I almost missed it. You did.
We had to wait for sunset. It was the longest afternoon of my life.
Cassian spent most of it teaching me. How to hear a heartbeat and then tune it out. How to breathe, even though I didn't need to, because the rhythm kept my hunger quiet. How to feel the red thing that had woken inside me on the roof, and how not to reach for it unless I was ready to pay.
"The Kneel," he called it. "The Progenitor's Command. Valerian used it twice in his entire life. Both times, it nearly killed him."
"It didn't hurt me," I said.
"It will." He looked at me with something that might have been sorrow. "It always does, eventually. It takes as much as you give it. And you do not yet know how much you have."
Marcus slept on and off, in bursts of ten minutes. Each time he woke, the lines on his arm had crept a little higher. By four o'clock they had reached his shoulder.
Near sunset, while Cassian went down to scout the stairwell, Marcus sat beside me. He didn't say anything for a while. He looked at his arm, and then at the sky through the broken roof, slowly turning orange.
"If I turn into a door," he said finally, "and you can't stop it, promise you won't hesitate."
"Marcus—"
"I mean it. Don't do your hesitation face."
"I'm not going to let it happen."
"That wasn't the promise." He tried to smile. It was a terrible attempt. "And the other thing. The blood thing. Promise me you won't do it just because you're scared. I don't want to be something you made because you panicked."
My throat closed. "Okay."
"Okay." He bumped my shoulder with his. "Besides, I'd be a terrible servant. I'd never shut up."
I laughed. It hurt.
At dusk, we left.
Saint Mercy Hospital sat at the end of a dead street, a huge brick ruin with its windows gone and its doors chained. Ivy ate the walls. The sign over the entrance had lost half its letters and read, simply, ERCY.
The blood moon rose behind it, swollen and dim, and it looked like the building was holding it in its teeth.
"I don't like this," Marcus said.
"Nobody likes it," said Cassian. "Stay between us."
We went in through a side door that had been pried open long ago. The corridor beyond smelled of mold and rust and old medicine, with something else beneath it. Something sweet. Lilies, I thought, and my stomach tightened.
The deeper we went, the louder the silence got. It pressed against my ears like water. Then, from somewhere ahead, a voice drifted down the hall, thin and warbling.
Nurse? Nurse, is anyone there? I'd like some water.
An old woman's voice.
Cassian's hand went to his blade. "Do not answer."
Nurse? Please?
Then another voice, a man's, low and cheerful. Almost done, folks! Just one more floor! A child giggled. A woman sobbed. A baby cried. A dozen voices, overlapping, drifting out of every dark doorway.
"It's stolen all of them," I whispered.
"Every patient who died here in the last year," Cassian said. "It has been keeping them."
David, said Marcus's voice, directly behind me.
I spun around.
Marcus stood three feet away, pale and sweating, his mouth closed. He hadn't spoken.
"It wasn't me," he said hoarsely. "I didn't—"
David, said Marcus's voice, from somewhere ahead, lilting and playful. David, I'm over here. Come help me!
"Don't," Cassian snapped.
But it was too late. The lights went out.
Everything happened in the dark.
I heard the Hollow before I saw it, a long, wet, scraping rush, like a hundred wet fingers dragging across the walls. I heard Cassian's blade leave its sheath. I heard Marcus yell my name, in his own real voice this time, and then something cut it off.
"MARCUS!"
I ran.
The corridor stretched and twisted around me. Every door I passed slammed open on its own, and out of each one poured a different voice: Help me. Help me. Don't leave me. Nurse. Nurse. Nurse. I could hear Marcus's heartbeat racing ahead, up a flight of stairs, around a corner. I could hear the quiet shape of the Hollow dragging him along.
"David!" Cassian's voice called, from somewhere to my left. "Kid, this way! I have him!"
I stopped dead.
Cassian had never once called me kid. In two days, he had said my name like it was a thing he was afraid to drop.
I went right.
I took the stairs in three leaps, hit a landing, kicked through a rusted fire door, and burst into the wide, high-ceilinged atrium at the hospital's heart.
The roof was gone. Moonlight poured through the broken rafters, red as old wine, and in the middle of the atrium floor, glowing faintly under the glare, was a circle.
It was drawn in white chalk, perfectly round, taller than I was. Inside it, symbols I couldn't read. Around its rim burned nine small black candles, flames standing perfectly still, with no breath of wind to move them. Scattered across the floor, thick as snow, lay white lily petals edged in red.
And in the center of the circle, on his knees, with his head hanging, was Marcus.
"Marcus!"
I tried to run to him. The moment my foot crossed the line of chalk, something slammed into me like an invisible wall and threw me backward across the floor.
Cassian skidded in beside me, breathing hard, blade drawn. "Do not touch it! It is a binding. If you cross it unprepared, it will take you too."
"He's in there!"
"I know." His eyes moved across the nine black flames, and his face went very still. "Nine candles. Nine is the number of a calling."
My stomach turned over. "I made nine calls that night."
"Then you were not calling for help," Cassian said quietly. "You were finishing the circle."
I didn't listen. I couldn't. I reached inside for the red thing, the one that had woken on Marcus's roof, and flung it at the circle with everything I had.
"Break."
The word tore out of me in that terrible chorus voice. For an instant, the chalk line shivered, and a hairline crack ran through the nearest candle flame.
Then the circle drank it.
All of it. Every drop of power I had thrown at it vanished into the symbols like water into sand, and the backlash hit me in the chest. I went down on one knee. Hot, copper-sweet liquid filled my mouth, and when I coughed, my hand came away red.
"I told you," Cassian said, and for once his voice was not cold. "It takes as much as you give it."
I pushed myself up, and that was when I saw the wall.
It ran along the far side of the atrium, a long stretch of cracked plaster, and something had been scrawled across it in dark, dried red. Huge letters, shaky and desperate, clawed into the wall by a hand that had been bleeding.
I knew that handwriting.
I'd been looking at it every day for years, on my homework, my receipts, my grocery lists. The crooked D. The slanting E.
DO NOT LET ME WAKE.
Below it, pressed into the plaster, was a handprint in dried blood.
I raised my own hand, slowly, and held it up beside it.
It fit perfectly.
"I wrote that," I whispered.
Yes, said the voice. And this time it did not sound calm, or patient, or kind. It sounded afraid. You did. Two nights ago, in the last hour before the moon reached its height. You came here, and you saw what was waiting, and you tried to stop it.
Stop what?
You did not stop it, the voice said. You only woke it faster.
"David," Cassian said sharply. "Look."
Inside the circle, Marcus lifted his head.
His eyes were white. The black lines ran all the way up his neck now, spreading across his jaw like cracks in glass. When he spoke, it was not one voice but dozens, the voices of everyone the Hollow had ever taken, speaking in perfect unison.
"Thank you for bringing him," they said. "You never could resist an invitation."
Around us, the nine black candles flared, all at once, burning blood-red.
The chalk circle ignited.
And Marcus rose slowly off the floor, arms spread wide, like a man being crucified on air, as the symbols beneath him began to turn.