“Back to the library, I suppose?” Ari said as Anna latched the Institute door firmly behind them. “To find the next candidate?”

“We cannot keep doing this,” Anna said wearily. “If we had all the time in the world, we could try every likely hill and dale in London. But we have barely any time at all.”

“Perhaps we should focus on making a longer list from our research first,” Ari said. “Then at least we could check several spots in the same part of the city.”

“I think we should find the five likeliest,” Anna said as they started up the central staircase, “and visit them, wherever they might be.”

“Only five?”

“We may not even have time for five,” Anna said. “Our situation here is untenable for very much longer.” She sighed. “Perhaps Grace will find a way to signal for help. Or perhaps Cordelia and Lucie will have some success in Edom. Or…” She trailed off, but Ari knew what she was thinking. “Or at least,” Anna said in a quieter voice, “we will have made a last stand.”

“Anna,” Ari said, taking her by the shoulder. Anna stopped and turned to look at her. “Before we consider our last stand, may I suggest we eat something? And maybe have some tea before we go out again.”

Anna smiled faintly. “Tea?”

“We will do no one any good,” said Ari firmly, “if we collapse from hunger or thirst.”

She was going to go on but was stopped by a muffled voice coming from the other end of the corridor. “What was that?”

“It’s coming from the infirmary,” Anna said, starting toward the sound. “It sounds like Alastair.”

Ari hurried to follow Anna. The infirmary door was closed; Anna opened it cautiously. Inside they found Thomas, who was sitting at the end of one of the beds, and Alastair, who was standing between him and the door. Thomas was glowering. “You cannot make me stay here.”

“I can,” Alastair said with feeling. “I will. I shall sit on you if necessary.”

Thomas folded his arms, and Ari noticed with a start that he looked as though he’d lost a fight. There was blood in his sandy hair, and bruises around one of his eyes, despite two fresh iratzes on his arm. He—and also Alastair, she realized—were scratched up and dusty all over.

“By the Angel,” Anna said, “what happened to you two? You look as though you’ve been in a pub fight. And were quite outnumbered. Whereas I am fairly sure the pubs are all closed.”

“We figured out how to kill the Watchers,” Thomas said eagerly. “Shall I tell you the story?”

“At once,” Anna said, and Thomas did, reporting their trip to Paddington Station and the battle that had ensued there. “There are runes on the backs of their necks,” he said. “A bit like Belial’s sigil, but modified in a few ways.”

“Perhaps to signify possession,” Alastair put in, “though neither of us are exactly experts on demonic runes.”

“If that rune is cut or destroyed,” Thomas went on, “it forces the demon out of the body. And then the demon itself can be killed with little trouble.”

Anna’s eyebrows went up. “Well, I don’t wish to overstate our position, but that seems… like good news? Rather unexpectedly?”

“It is hard to think of a downside,” Alastair said reluctantly. “And I have tried.”

“The downside,” said Ari with a frown, “is that even with this knowledge, a Watcher is a tough fight. One must find an opening to strike the back of the neck without being knocked down by strength or magic.”

Thomas nodded. “And there are a lot of them,” he said. “And only a few of us.”

“What we need is for Jesse and Grace to make the fire-messages work,” said Ari. “What we need is an army.”

“Still, we are one step closer to saving London,” Thomas said.

Alastair gave him a withering look. “I see the blow you have suffered to the head is worse than I had realized. We are nowhere near saving London.”

“Besides, it’s not quite London we’re saving, is it?” said Anna thoughtfully. “London will remain. Only its people will be gone. Its life.”

Alastair waved his hand. “Yes, yes. It has been Roman and Saxon and now it will be demon. It has survived plague and pestilence and fire—”

“Of course!” Anna shouted, causing everyone to jump. “The Great Fire!” With a wild look in her eye, she tore out of the infirmary.

The others looked at the open doorway where she had disappeared. “I don’t think any of us expected that,” Thomas said.

“I’ll go see what’s happened,” Ari said hesitantly.

“Right,” said Thomas. “We’ll fetch Grace and Jesse from wherever they’ve gotten to. They must be told that the Watchers can be beaten.”

He began to get up from the bed; Alastair gently pushed him back down on it. “I will fetch Grace and Jesse,” he said. “You will rest.”

Thomas looked over at Ari with a plaintive look.

“I’m sorry, Thomas, but he’s right,” Ari said. “You must allow yourself some time to recover, or you won’t keep your strength up.”

“But I’m fine—”

Leaving Thomas and Alastair to argue, Ari went and found Anna in the library, standing over one of the study tables. As Ari got closer she could see that Anna had a tattered map, deeply yellowed with age, spread out before her. When she looked up at Ari, there was—for the first time since Christopher’s death—actual excitement in her eyes.

“Have you ever noticed,” she said, “that the entrance to the Silent City is quite far from central London, all the way up in Highgate?”

“I have noticed,” Ari said slowly. “I never thought much about it. I suppose it is a bit far from the Institute.”

“Well, it wasn’t always,” said Anna, jabbing her finger down at the parchment. “They moved it after the Great Fire of London. This map here is from 1654, and this is the old entrance to the Silent City.”

Ari looked. “That is much closer,” she said. “It’s just on the other side of St. Paul’s from us.”

“At the church of St. Peter Westcheap,” Anna said. “Which burned in the Fire, in 1666.” She tapped the map with her finger. “Don’t you see? If we can get into the Silent City through an unguarded entrance, we can find the Path of the Dead. Retrace the route that the Watchers took from the Iron Tombs.”

“You mean if we can make it to the Iron Tombs, then we will have escaped Belial’s sphere of influence. We will be able to contact Alicante.” Ari clasped her hands together. “Or if by some miracle the Blackthorns get fire-messages working, we could have reinforcements meet us at the Tombs—”

“And,” said Anna, “we could then lead those reinforcements into the Silent City, and from there, right back to London.”

Sparked by a sudden rush of hope, Ari leaned across the table and kissed Anna full on the mouth. She pulled back a little, enjoying the look of surprise on Anna’s face. “You are the most devilishly clever schemer.”

Anna smiled. “It’s because you bring out the best in me, darling.”

At the time, he only listened. Matthew told the story simply and directly: Alastair’s taunts about his mother, his own visit to the Shadow Market, his purchase of the faerie potion to give to an unknowing Charlotte. His mother’s violent illness, her miscarriage.

“I remember,” James breathed. A wind had come up; he could hear it howling over the plains beyond the courtyard walls. “When your mother lost the baby. Jem treated her—”

“Jem knew,” Matthew said. “He saw it in my mind, I think, though I refused to speak about it with him. Still, I remember what he said then. ‘I will not tell anybody. But you should. A secret kept too long can kill a soul by inches.’ Advice,” Matthew added, “that I, being a fool, did not take.”

“I understand,” James said. “You dreaded to tell it. To tell what happened was to live it again.”

“That is true for you,” Matthew observed. “I saw your face when you spoke of the bracelet, of Grace. It was as if a wound had reopened for you. But for me—I am not the one who suffered, James. My mother suffered. My family suffered. I caused it. I am not the victim.” He sucked in a breath. “I think I might be sick again.”

James ruffled Matthew’s hair gently. “Try to keep the water down,” he said. “Math—What I hear is a story of someone making a terrible mistake. You were young, and it was a mistake. It had no evil in it, no volition to harm your mother or anyone. You were rash and trusted wrongly. There was no malice.”

“I’ve made many bad decisions. None of them have ever had consequences like this.”

“Because,” said James, “you ensure that the worst results of your decisions always fall upon yourself.”

Matthew was silent for a moment. “I suppose that’s true,” he said.

“Your bad decision did have terrible, unforeseeable consequences,” James went on. “But you are not the devil incarnate, or Cain condemned to wander.” His voice softened. “Imagine me a few years ago. Imagine I came to you and told you this story, that I was the one who made the mistake. What would you say to me?”

“I would tell you to forgive yourself,” said Matthew. “And to tell the truth to your family.”

“You have brutalized yourself for years over this,” said James. “Try now to be as kind to yourself as you would have been to me. Remember that your sin is your silence, not what you did. All this time you have pushed Charlotte and Henry away, and I know what it has cost you. What it has cost them. Matthew, you are also their child. Let them forgive you.”

“That first night,” Matthew said, “after it happened, I took a bottle of whiskey from my parents’ cupboard and drank it. I was vilely sick afterward, but for the first few moments, when it dulled the sharpness of my thoughts and senses, the pain faded. Went away. I felt a lightness of heart, and it is that I have been seeking again and again. That surcease.”

“Your heart will always want that oblivion,” said James. “You will always have to fight it.” He laced his fingers through Matthew’s. “I will always help you.”

Several dark shapes flew by overhead, shrieking. Matthew watched them go, frowning. “Belial will return tomorrow,” he said. “I do not think he will leave you alone for long.”

“No,” James said. “Which is why I have been thinking. I have a plan.”

“Really?”Matthew said. “Well. Thank the Angel.”

“You won’t like it,” James said. “But I must tell it to you, regardless. I will need your help.”

Her chest felt tight as she and Cordelia toiled up another sand dune. The sand, dust, and soot in the air made it hard to breathe, but it was more than that: it was the weight of death all around her. As she followed the sensation that drew them closer to Idumea, it pressed down on her like a stone. Her joints ached, and there was a dull pain behind her eyes. It was as though something primordial within her cried out against Edom; she was a Shadowhunter, and in her flowed the blood of angels. She had never thought what it might mean to be in a place where long ago all angels had been slain.

Heat shimmered on the horizon. At the top of the dune, they paused to orient themselves, and to drink a little water. Both of them had brought flasks, but Lucie doubted what they had would last them more than a day or two.

She squinted into the distance. Stretching out before them, at the base of the dune, was a plain of black, glittering sand, like beads of jet. Where it met the horizon, something solid rose against the sky—jagged like the peaks of hills, but far too regular to be natural.

Cordelia had tied a scarf around her hair; her eyebrows were whitened with ash. “Is that Idumea?”

“I think those are towers,” Lucie allowed, wishing her Farsighted rune was working. She thought she was looking at towers and walls, but it was impossible to be entirely sure. She dusted biscuit off her hands and said, “It’s in the direction of Idumea, at least. We’ll have to go that way regardless.”

“Hmm.” Cordelia looked thoughtful but didn’t object. They clambered down the dune’s far side and started across the sea of black, quickly discovering that it was a mixture of sand and pitch: tarry, sulfur-smelling muck that stuck to their boots and sucked at their feet with every step.

“I haven’t felt this trapped since Esme Hardcastle tried to find out how many children I intend to have with Jesse,” said Lucie, yanking her foot free.

Cordelia smiled. “She did that to you, too?”

“Esme thinks she knows exactly who is going to marry who, and who is going to die when. Some people she thinks are alive are dead, and there are people who are dead who she is convinced are actually alive. This is going to be quite the family tree. It will confuse scholars for decades.”

“Something to look forward to,” Cordelia agreed. She hesitated a moment before she spoke again. “Luce, you can sense things about this world. Do you feel… anything about James and Matthew?”

“No,” Lucie said. “But I think that’s a good thing. I can sense the dead. If I don’t sense them, then…”

“They’re still alive.” Cordelia was clearly clutching at the idea; Lucie didn’t want to say she wasn’t as reassured herself.

They had nearly reached the end of the black sand. Cordelia was frowning. “I don’t think this is Idumea. It’s just…”

“A wall,” Lucie finished. They were in its shadow now, looking up. It rose perhaps thirty feet in the air, a construction of smooth gray stone that stretched in either direction as far as she could see. There were no other buildings or ruins to be seen: what Lucie had thought were towers were the wall’s battlements high above. It was completely smooth, dashing any thought of climbing it. They would have to find a way through.

They began to pace the length of the wall, heading away from the sun, which hung halfway to the horizon now, searing across the level sand. It didn’t take them long to find a gate: an elaborate carved arch that opened into the dark interior of the wall.

There was something Lucie didn’t like about that darkness. It felt cave-like, and she realized they had no idea how thick the wall was. They could be walking into a tunnel, or any sort of trap. Sand blew across the entrance, dimming the interior even further.

Yet she could still feel Idumea, pulling at her even harder now, telling her she had to pass this wall and keep going. She took a hand axe from her weapons belt and glanced over at Cordelia, who had drawn Cortana. The golden sword glinted in the harsh sun. “All right,” she said. “Let’s see if we can get through.”

They ducked through the archway and found themselves in a stone-sided corridor with a barrel roof. As they walked, the packed sand floor gave way to more stone. They were in a tunnel that bored through the wall, illuminated on the inside by a spongy, phosphorescent moss that clung to the walls. Lucie moved closer to Cordelia—the air was cold, and the smell of damp stone bitter. Lucie thought she could hear water trickling somewhere and recalled what Lilith had said about the water of Edom being poison.

Cordelia tapped her shoulder lightly. “Something’s glowing,” she said. “Up ahead.”

For a moment, Lucie let herself hope it was the end of the tunnel, the far side of the wall. Even the sandblasted desert of Edom seemed preferable to the tunnel. But as they drew closer and the glow intensified, the tunnel widened around them, expanding into a stone chamber filled with tallow candles: they were stuck in every crack and crevice, filling the space with flickering light.

Within a pentagram formed of dark red gems sat an oversized throne of black obsidian, on which squatted a scaly blue creature, lizard-tailed, with a downturned, froglike mouth and yellow-orange eyes. Hovering beside the throne, in midair, was a massive skull—not human or animal, but demon, with holes for far too many eyes, and threaded through those holes were a dozen black, oily tentacles. Each tentacle gripped a long silver feather, with which the skull fanned the blue demon on the throne.

“Oh my,” the demon said, in a surprisingly high-pitched voice. “Nephilim. How unexpected.” It shifted, and Lucie saw that in one clawed hand it held what seemed to be a bunch of grapes. “Welcome to my court. I am here to collect a toll from all who wish to pass the Wall of Kadesh.”

Whatcourt? Lucie wondered. Other than the skull, and it didn’t seem particularly alive, there seemed to be no courtiers here, no real place for a court, if there was one, to assemble. All she could see was a peculiar variety of sun-bleached bones, long and white, stuck into the ground at odd intervals.

“What kind of toll?” Cordelia asked. She hadn’t lifted Cortana, but she was gripping the hilt tightly.

“The kind that will please me,” said the demon, plucking a grape from the bunch he held and popping it into his gaping mouth. Lucie was quite sure she heard the grape scream in terror as it was eaten. “I am Carbas, Dux Operti. I am a collector of secrets. Long ago, Lilith gave me leave to set up my court here so that I may collect them from travelers passing by.”

Cordelia and Lucie exchanged looks: Did Duke Carbas know that Lilith was gone, and Belial had taken her place as ruler of Edom? If he never left this spot, perhaps he didn’t; either way, Lucie wasn’t inclined to tell him.

“You collect secrets from passing demons?” Cordelia said.

“I didn’t think demons had secrets,” Lucie mused. “I thought they’d be proud of all the evil they did.”

“Oh, they are,” said Carbas. “Which makes it a very boring job. ‘Oh, I saved a kitten from a Ravener demon, Carbas, and I’m so ashamed.’ ‘Oh, I failed to turn anyone toward the dark side last week, Carbas.’ Whine, whine, complain. But you, Nephilim, with all your morals—you will have juicy secrets.”

He popped another grape into his mouth. This one definitely screamed.

“What happens,” said Lucie, “if we try to pass through without telling you a secret?”

Carbas leered coldly. “Then you will find yourself trapped in this tunnel, and soon enough will become a member of my court.” He gestured at the bones jutting from the ground, which began to vibrate. “We’d all like that, wouldn’t we?” He chuckled. “New blood, as it were.”

Trapped in the tunnel.Lucie tried not to look worried: dying in battle was one thing. Being trapped in this dank, demon-haunted tunnel until they died was something else.

“So please,” Carbas went on, grinning wetly, “whenever you’re ready, a secret from each of you. It must be something you have told no one else, something you wish no one to know. Otherwise, it is worth nothing to me. And I will be able to tell if you are making something up. You must tell a secret from the heart,” he added, somehow making the phrase “from the heart” sound vicious. “One that means something to tell.”

“These rules seem vague,” said Cordelia. “And subjective.”

“That’s magic for you.” Carbas shrugged.

Lucie and Cordelia exchanged a look. They could try to attack Carbas, of course, but that would mean stepping into the pentagram with him, a deeply risky choice. Yet the thought of offering up her most hidden thoughts to Carbas, to snack on as he did the grapes, felt violating and cruel.

It was Cordelia who stepped forward first. “I have a secret,” she said. “It isn’t something nobody knows, but it is something Lucie doesn’t know.” She looked over at Lucie, her eyes pleading. Lucie bit her lip. “And that’s what matters, isn’t it?”

“Mmm. I’m interested,” Carbas said. “Let’s hear it.”

“I’m in love with James Herondale,” Cordelia said. “Lucie’s brother.”

“Well, of course you are,” Lucie said, before clamping her mouth shut.

Carbas rolled his eyes. “Not off to a great start.”

“No,” Cordelia said, a little desperately, “you don’t understand. I didn’t just fall in love with him when I came to London, or when we got married. I’ve been in love with him for… for years,” she went on. “Ever since he had the scalding fever.”

Thatlong ago? The thought jolted Lucie. But…

“I never told you about it, Lucie. Every time you mentioned him, I would lie about how I felt, or make a joke. When you suggested that I might entertain romantic thoughts about James, I would act like it was the most ridiculous idea on earth. When we got engaged, I acted as if I couldn’t wait for it to be over. I didn’t want to be pitied, and I didn’t want to be just another of the silly girls who was in love with your brother while he only cared about Grace. So I lied to you.” She took a deep breath. “It’s like you said at my house that night, Lucie. I was too proud.”

But you could have told me. I would never have pitied you,Lucie thought, bewildered. She didn’t mind that Cordelia had been in love with James—but the lying, the hiding… she wished it didn’t bother her, but it did. She looked away from Cordelia—and saw Carbas on his throne, smacking his lips.

“Not bad,” he murmured. “Not terrible.” His yellowish eyes slid over to Lucie. “Now what about you?”

Lucie stepped forward, taking Cordelia’s place before the throne. She didn’t look at Daisy as she did so; if she hadn’t known this important thing about her best friend, had she ever really known her at all? Had Cordelia ever really trusted her?

She told herself to stop, that this was what Carbas wanted. Their pain. His amber demon’s eyes were already fixed on her with anticipatory delight. “I have a secret,” she said. “One nobody knows.”

“Ooh,” said Carbas.

“When Cordelia and I tried to practice our parabatai ceremony,” she said, “I couldn’t go through with it. I didn’t tell her why. I pretended as if nothing had happened, but that—that wasn’t true at all.” She glanced over her shoulder at Cordelia, who was holding Cortana so tightly her knuckles were white. “When we began to speak the words,” Lucie said, “the room filled with ghosts. Ghosts of Shadowhunters, though none I knew. I could see them everywhere, and they were staring at us. Usually I can understand the dead, but—I didn’t know what they wanted. Did they disapprove of my creating a bond to someone living? Or did they want me to do it? I thought—what if going through with it bonded you, too, to the dead?”

Cordelia had gone a sickly color. “How could you not tell me that?” she whispered. “You were going to go ahead with the ceremony, then, without warning me? What if something had happened to you during it—what if the ghosts meant harm?”

“I was going to tell you,” Lucie protested. “But then the thing with Lilith happened, and you told me that we couldn’t become parabatai—”

“Yes, because I thought I owed you the truth before we bonded ourselves together.”

Carbas moaned in pleasure. “Don’t stop,” he groaned. “This is wonderful! It’s rare I get two people telling secrets about each other. I haven’t enjoyed a revelation this much since I found out Napoleon always hid his hand inside his jacket because he kept a spare sandwich there.”

He leered again.

“Oh, ugh,” said Lucie, thoroughly revolted. “That’s enough. We’ve done what you asked—by your own rules, you have to let us leave.”

Carbas sighed and looked sadly at the flapping skull, as if seeking sympathy. “Well, if you return this way, do stop by and see old Carbas.” As he spoke, a hidden door in the far wall swung open. Through it Lucie could see the familiar bloody orange light of Edom. “But then again,” Carbas added, as Lucie and Cordelia made their way to the door, “this is Edom. Who are we trying to fool? You’ll be lucky to make it to nightfall, Nephilim. You certainly won’t be coming back here.”