I asked Corvin for the code at one in the morning, and it was the riskiest thing I had done since the butcher's shop.
She was standing alone at the edge of the rail yard, a lantern shuttered at her feet, watching the dark the way sentries do when they have nothing left to watch for. She did not turn when I came up beside her. She did not need to. I think she had been waiting for me to find her again.
"Wardens signal by flash," I said. "On long watches. Mirror or lamp."
"Some do."
"There was a signal tonight. Two flashes, a pause, answered once from the roof of the long hall." I kept my voice low. "I'd like to know what it said."
Corvin was silent for a while. Far off, the furnace ticked as it cooled.
"You're asking me to read my own people's talk to you," she said.
"I'm asking whether it was your people's talk at all."
That reached her. Her shoulders shifted, very slightly, under the grey coat.
"The Warden code is short," she said at last. "Long flash, short flash, counted in threes. A group of three is a letter. We use it for position and numbers, mostly. Nothing fancy." She picked up the lantern and turned its shutter a quarter inch, showing me the small brass slide. "Two flashes with a pause is the opening mark. It means a message follows."
"And the answer?"
"A single flash is only acknowledgment. It doesn't say anything." She frowned. "But a Warden wouldn't answer from a roof in the middle of a watch. We're ordered to stay below the eaves."
"So someone who isn't a Warden knows your opening mark."
"Or someone who is, and doesn't care about the order." She closed the shutter. "I can't tell you which. I can tell you that if you climb that tower, you should expect whoever's up there to be listening."
"I'm not climbing it to listen."
"No," said Corvin. "I didn't think so."
She did not say good luck. She stood and watched me go, and I felt her eyes between my shoulder blades until I turned the corner of the smithy.
◆
The second cooling tower was a hundred and ten feet of black brick, bulging at the waist like a bottle, with an iron ladder running up one side and half its rungs missing.
Kaelen had brought two ropes, a hammer, and a pair of leather gloves that had belonged to somebody with smaller hands. He tied me in with a knot I did not recognize and tested it twice with his full weight.
"It holds," he said.
"You sound surprised."
"I'm never surprised by rope. I'm surprised by people." He looked up the length of the tower, a pale line of rungs vanishing into the haze. "Stay on the left side of the ladder. The right side is rusted through every third rung."
"How do you know?"
"I climbed it at dusk, while you were sorting iron." He met my eyes without apology. "I wanted to know what we were walking into."
"You didn't tell me."
"You'd have said no."
"I'd have said you should have told me."
"Then we agree," said Kaelen, "and I'm sorry."
It was such an unexpected thing to hear from him that I forgot to be annoyed. I took hold of the first rung, and the iron bit cold through the borrowed gloves.
"I'll go first," he said.
"I'm the one who wants to ask the question."
"And I'm the one who knows which rungs hold." He was already climbing. "You can ask it at the top."
◆
I had never been afraid of heights until that ladder.
The Undercity spread out below us as we rose, a sprawl of red furnace glow and black roofs, and every ten feet the wind found a new way to shove at my back. Kaelen climbed above me in steady, unhurried motions, calling down the position of each missing rung in a low calm voice. Skip this one. Left foot here. Don't trust the weld. I did what he said. My arms burned by the sixtieth rung, and my head had begun to throb in the old familiar rhythm, though I had told no lie in hours.
Somewhere around the ninetieth, I looked down and wished I had not.
The Row lay a hundred feet beneath us, small and dim, the furnace a single orange eye in the dark. I could see the long hall where the Wardens slept. I could see the west hall, where a girl in a linen band was probably lying awake. I could see the dull gleam of the cart wheels over the hatch.
And on the roof of the long hall, so faint I almost missed it, a small bright wink of light.
"Kaelen," I said.
"I saw it."
"Is it answering something?"
"No." His voice came down tight. "It's waiting."
We climbed the last twenty feet faster than I thought I could.
◆
The top of the tower was a ring of crumbling brick, about twelve feet across, open to the air. A low parapet circled it like the rim of a cup. In the middle sat a battered iron brazier with its fire long cold, and a cot, and a crate with a tin cup and half a loaf of bread on it.
It looked exactly like the empty room in the foreman's office. That was the first thing that bothered me.
The second was the mirror.
It stood on a tripod at the east edge of the parapet, a round polished disc the size of a dinner plate, angled out toward the Row. Beside it, on a hook, hung a shuttered lamp with a brass slide. Beside that sat a slate with a stub of chalk, and on the slate, in a tidy cramped hand, were rows of little marks. Long strokes and short ones, grouped in threes.
Kaelen crouched in front of it with his hand on the parapet, and I knelt beside him, and neither of us said a word.
The slate had been written only an hour before. The chalk was still bright.
Three groups. Then a gap. Then four groups. Then another gap, and a long sequence ending in a double stroke I recognized from Corvin's lantern.
"That's the opening mark," I said.
"What does the rest say?"
"I don't know the code."
"Then we copy it," said Kaelen, and pulled a folded paper and a pencil from his coat.
"You came prepared."
"You asked for a rope. I brought a pencil. It's not a sacrifice."
I almost laughed. Then the dark behind us moved.
◆
It came from the cot.
I had assumed it was empty. A heap of grey sacking lay across it, and I had looked at it the way you look at furniture. Now the heap sat up, and I saw it was a person, small, hooded, perfectly still, with a bare foot hanging off the edge and a heavy boot beside it on the floor.
"Don't touch the chalk," said a voice.
It was a girl's voice. Perhaps fifteen. Dry and a little hoarse, and entirely without fear.
Kaelen was on his feet before I could blink, one hand on the empty belt where a sword should have been. The girl did not so much as flinch. She sat on the edge of the cot with her knees together and her hands in her lap, and the hood fell back from a small, sharp, tired face with hair cut crooked by a knife.
"You've been up here the whole time," I said.
"Since dusk."
"Watching us climb."
"I watched you climb. I watched him climb earlier." She nodded at Kaelen. "He's better on a rope than you."
"I'm aware."
"The rungs on the right are rotten. You should have told him."
"He told me."
"Good." She looked from one of us to the other, and I saw something in her eyes I recognized. It was the look of a person who had decided to talk and had not yet decided how much. "You're the claimant. From the Row."
"Aren."
"Sparrow." She said it flatly, like a password. "It isn't my name. It's the name I use up here."
"Who do you work for?"
"That's the wrong question."
"Then what's the right one?"
"Who do you think I work for?" She tilted her head. "Because you've already decided. You've been deciding since you found the cloth."
I thought of the neat grey stitches. The tiny mirror. The three unfinished letters. I thought of the Broker's cold quiet voice at the foot of the Pit stairs saying, Someone is using my name in the dark.
"Someone who wants me to think it's the Broker," I said.
Sparrow gave a short dry laugh. It was almost approving.
"Her mirrors are older than mine," she said. "Better. She'd never stitch a thumbnail one on a rag. That's the first thing anyone who'd ever seen her house would notice." She picked at the hem of her sleeve. "I told him that. He said you wouldn't know."
"Him."
"I said that on purpose," said Sparrow. "You can have it free."
◆
Kaelen shifted his weight, and she looked at him, and some of the stiffness went out of her shoulders.
"You're not going to hit me," she said.
"No."
"You were going to."
"I was going to tie you to the brazier and ask questions." He glanced at the slate. "I've changed my mind."
"Why?"
"Because you've been polite."
It was such a nobleman's reason that she blinked. Then, very slightly, she smiled. It was a small crooked smile and it did not last, but I saw it, and I understood that Sparrow had spent a long time alone on top of a tower with nobody to be polite back to.
"I send what I'm told to send," she said. "I read what comes back. That's all. Nobody ever told me what the words meant." She nodded at the slate. "Before you ask. I didn't pack the powder. I wasn't down there. I was up here, all afternoon, signaling."
"Signaling what?"
"The count." She said it as if it were obvious. "How many people in the chain. How many left the furnace. When the yard was empty enough."
The ache behind my left eye gave a hard single throb.
"You told someone when it was safe to pack the nozzles," I said.
"I told someone when the yard was empty. I didn't know what for." Her voice dropped. "I found out afterward, from the talk in the Row. I stopped signaling for an hour. I thought about leaving." She looked down at her hands. "I didn't leave."
"Why not?"
"Because he knows where my brother is."
It fell between us like a stone into water. Nobody spoke. Far below, the furnace ticked.
"Who is he?" I said, very quietly.
"I don't know." She shook her head. "I never saw his face. Just a coat, and a voice, and a purse on the cot every time. Grey coat. Always grey."
"A Warden's coat."
"A grey coat," said Sparrow. "I didn't say Warden. You did."
"It could be forged."
"It could be anything." She looked up, and her eyes were wet and furious and young. "I'm telling you because you asked me politely, and because nobody ever has. Don't make me sorry."
"I won't."
"Everybody says that."
"I know," I said. "I've said it to a lot of people this week. So far I've kept it."
She searched my face for a long moment. Whatever she found there, it was enough.
◆
"The slate," I said. "The last message. What did it say?"
Sparrow hesitated. I saw her weigh it, and I saw her decide.
"I'm not supposed to decode it for anyone."
"I'm not asking you to decode it for me. I'm asking you to tell me whether it's something I should be afraid of."
She looked at the slate, and then at me, and her mouth thinned.
"It's short," she said. "I sent it an hour ago. Four words and a place."
"What words?"
"Girl. Band. Eyes. East."
For a moment I did not understand. Then I understood all at once, the way you understand a floor has gone from under you.
"East hall," I said.
"That's what the place means."
"The Hospice kitchen is on the east side."
"I don't know the Row," said Sparrow. "I only know what I'm told to send." She went very pale. "Is that someone you know?"
I did not answer. Behind me, Kaelen drew a sharp breath. I heard the scrape of his boot on the brick, and the quick hard clatter of the rope as he snatched it from the parapet.
"Who read it?" I said. My own voice sounded strange to me, flat and far off. "Who answered?"
"One flash from the roof of the long hall. That means received."
"Received by whom?"
"I can't see faces from here."
"Sparrow."
"I can't." She was crying now, silently, with her hands shut tight in her lap. "I swear I can't. I only know there's someone there, and they know the opening mark, and they've known it for weeks."
"One of the Wardens."
"Or someone sleeping near them."
I turned to Kaelen. He was already knotting the rope around the iron ring set in the parapet, and his hands were quick and sure, and his face was a color I had not seen before.
"How long to get down?" I said.
"Six minutes, if I don't care about the rungs."
"Care about the rungs."
"Five."
"Kaelen."
"Four," he said, and was over the edge.
I looked back at the girl on the cot. She had not moved. She sat very small in the cold brazier light, with the mirror at her back and the chalk marks on the slate beside her like a row of tiny teeth.
"Come with us," I said.
"I can't."
"Your brother."
"If I leave, he's gone." She shook her head, quick and fierce. "If I stay and keep signaling, he's alive. That's how it works."
"That isn't how it works."
"It's how it works for me." She wiped her face with the back of her wrist. "Go. You've got a girl to find."
I wanted to say something. I did not know what. I wanted to promise her a thing I could not afford to promise, and I wanted to be someone who could.
"I'll come back," I said. "For you. For him. I'll find out who he is."
"Everybody says that."
"I know," I said, and took hold of the rope.
◆
We dropped the hundred and ten feet in under four minutes.
I do not remember most of it. I remember the rope searing my gloves. I remember a rung giving way under my right foot and Kaelen's hand closing on my collar from below. I remember the ground coming up out of the dark, and the hard jar of it through my knees, and the sound of my own breath ragged in my ears.
We ran.
The Row was silent. The long hall stood dark, its windows black, and I did not stop to look at it. The cold smithy swept past. The furnace glowed on my left like a patient eye. Ahead, at the far end of the west yard, the east hall's low roof rose against the haze, and in the narrow window of the kitchen, a single lamp was burning.
I ran faster.
Behind me, I heard Kaelen's boots pounding, and I heard, somewhere to my right, a sound I had not heard in six days. It was the low rhythmic creak of a door opening very slowly on a hinge that had been oiled that afternoon.
I turned my head.
In the shadow beside the long hall, a grey coat stood motionless, with the lantern at its feet. It was not looking at me. It was looking at the kitchen window.
I could not see its face. I could not see its hands. But I saw the slow deliberate way it bent and picked up the lamp, and the small neat motion of its thumb on the brass slide, and I knew what it was about to do.
I shouted.
I do not know what I said. It might have been Lyra's name. It might have been nothing at all. The grey coat jerked its head toward the sound, and for one terrible instant I saw a pale oval of face above the collar, caught in the light of the furnace.
Then the lantern went out, and the figure was gone.
The kitchen door banged open at the far end of the yard.
Lyra stood in it, a thin pale shape against the lamplight, one hand lifted to the linen band over her eyes. For a long moment nobody moved.
Then she lowered her hand, slowly, and I saw she had taken the band off.