"As dull as Nate Gray is," Will said, "his head is not actual y fil ed with gears, Henry. He's a human."

"He may bring one of those creatures with him. We don't know he'l be there unaccompanied. If nothing else, that clockwork coachman of Mortmain's-"

"I think Henry is right," said Tessa, and they all whirled to face her. Jem flushed again, though more lightly this time, and offered her a crooked smile; Will 's eyes ran up and down her body once, not briskly.

He said, "You don't look like a boy at all. You look like a girl in boys' clothes."

She couldn't tell if he was approving, disapproving, or neutral on the subject. "I'm not trying to fool anyone but a casual observer," she replied crossly. "Nate knows Jessamine's a girl. And the clothes Will fit me better once I've Changed into her."

"Maybe you should do it now," said Will.

Tessa glared at him, then shut her eyes. It was different, Changing into someone you had been before. She did not need to be holding something of theirs, or to be near them. It was like closing her eyes and reaching into a wardrobe, detecting a familiar garment by touch, and drawing it out. She reached for Jessamine inside herself, and let her free, wrapping the Jessamine disguise around herself, feeling the breath pushed from her lungs as her rib cage contracted, her hair slipping from its twist to fal in light corn silk waves against her face. She pushed it back up under the hat and opened her eyes.

They were all staring at her. Jem was the only one to offer a smile as she blinked in the light.

"Uncanny," said Henry. His hand rested lightly on the object on the table.

Tessa, uncomfortable with the eyes on her, moved toward it. "What is that?"

"It's a sort of . . . infernal device that Henry's created," Jem said. "Meant to disrupt the internal mechanisms that keep the clockwork creatures running."

"You twist it, like this"-Henry mimed twisting the bottom half of the thing in one direction and the top half in another-"and then throw it. Try to lodge it into the creature's gears or somewhere that it Will stick. It is meant to disrupt the mechanical currents that run through the creature's body, causing them to wrench apart. It could do you some damage too, even if you aren't clockwork, so don't hang on to it once it's activated. I've only two, so . . ."

He handed one to Jem, and another to Charlotte, who took it and hung it from her weapons belt without a word.

"The message has been sent?" Tessa asked.

"Yes. We're only waiting for a reply from your brother now," said Charlotte.

She unrol ed a paper across the surface of the table, weighting down the corners with copper gears from a stack Henry must have left there. "Here,"

she said, "is a map that shows where Jessamine claims she and Nate usual y meet. It's a warehouse on Mincing Lane, down by Lower Thames Street. It used to be a tea merchant's packing factory until the business went bankrupt."

"Mincing Lane," said Jem. "Center of the tea trade. Also the opium trade.

Makes sense Mortmain might keep a warehouse there." He ran a slender finger over the map, tracing the names of the nearby streets: Eastcheap, Gracechurch Street, Lower Thames Street, St. Swithin's Lane. "Such an odd place for Jessamine, though," he said. "She always dreamed of such glamour-of being introduced at Court and putting her hair up for dances.

Not of clandestine meetings in some sooty warehouse near the wharves."

"She did do what she set out to do," Tessa said. "She married someone who isn't a Shadowhunter."

Will 's mouth quirked into a half smile. "If the marriage were valid, she'd be your sister-in-law."

Tessa shuddered. "I-it's not that I hold a grudge against Jessamine. But she deserves better than my brother."

"Anyone deserves better than that." Will reached under the table and drew out a rol ed-up bunch of fabric. He spread it across the table, avoiding the map. Inside were several long, thin weapons, each with a gleaming rune carved into the blade. "I'd nearly forgotten I had Thomas order these for me a few weeks ago. They've only just arrived. Misericords-good for getting in between the jointure of those clockwork creatures."

"The question is," Jem said, lifting one of the misericords and examining the blade, "once we get Tessa inside to meet Nate, how do the rest of us watch their meeting without being noticed? We must be ready to intervene at any moment, especial y if it appears that his suspicions have been aroused."

"We must arrive first, and hide ourselves," said Will. "It is the only way. We listen to see if Nate says anything useful."

"I dislike the idea of Tessa being forced to speak with him at all," muttered Jem.

"She can well hold her own; I have seen it. Besides, he is more likely to speak freely if he thinks himself safe. Once captured, even if the Silent Brothers do explore his mind, Mortmain may have thought to put blocks in it to protect his knowledge, which can take time to dismantle."

"I think Mortmain has put in blocks in Jessamine's case," said Tessa. "For whatever it is worth, I cannot touch her thoughts."

"Even more likely he Will have done it in Nate's, then," said Will.

"That boy is as weak as a kitten," said Henry. "He Will tell us whatever we want to know. And if not, I have a device-"

"Henry!" Charlotte looked seriously alarmed. "Tel me you have not been working on a torture device."

"Not at all. I call it the Confuser. It emits a vibration that directly affects the human brain, rendering it incapable of tell ing between fiction and fact."

Henry, looking proud, reached for his box. "He Will simply spil everything that is in his mind, with no attention to the consequences . . ."

Charlotte held up a warning hand. "Not right now, Henry. If we must utilize the . . . Confuser on Nate Gray, we Will do so when we have brought him back here. At the moment we must concentrate on reaching the warehouse before Tessa. It is not that far; I suggest Cyril takes us there, then returns for Tessa."

"Nate Will recognize the Institute's carriage," Tessa objected. "When I saw Jessamine leaving for a meeting with Nate, she was most decidedly going on foot. I shall walk."

"You Will get lost," said Will.

"I won't," said Tessa, indicating the map. "It's a simple walk. I could turn left at Gracechurch Street, go along Eastcheap, and cut through to Mincing Lane."

An argument ensued, with Jem, to Tessa's surprise, siding with Will against the idea of her walking the streets alone. Eventual y it was decided that Henry would drive the carriage to Mincing Lane, while Tessa would walk, with Cyril following her at a discreet distance, lest she lose herself in the crowded, dirty, noisy city. With a shrug she agreed; it seemed less trouble than arguing, and she didn't mind Cyril.

"I don't suppose anyone's going to point out," said Will, "that once again we are leaving the Institute without a Shadow-hunter to protect it?"

Charlotte rol ed up the map with a flick of her wrist. "And which of us would you suggest stay home, then, instead of helping Tessa?"

"I didn't say anything about anyone staying home." Will 's voice dropped.

"But Cyril Will be with Tessa, Sophie's only half-trained, and Bridget . . ."

Tessa glanced over at Sophie, who was sitting quietly in the corner of the library, but the other girl gave no sign of having heard Will. Meanwhile, Bridget's voice was wafting faintly from the kitchen, another miserable bal ad: "So John took out of his pocket A knife both long and sharp, And stuck it through his brother's heart, And the blood came pouring down.

Says John to William, 'Take off thy shirt, And tear it from gore to gore, And wrap it round your bleeding heart, And the blood will pour no more.'"

"By the Angel," said Charlotte, "we really are going to have to do something about her before she drives us all to madness, aren't we?"

Before anyone could reply, two things happened at once: Something tapped at the window, startling Tessa so much that she took a step back, and a great, echoing noise sounded through the Institute-the sound of the summoning bell. Charlotte said something to Will -lost in the noise of the bel -and he left the room, while Charlotte crossed it, slid the window up and open, and captured something hovering outside.

She turned away from the window, a fluttering piece of paper in her hand; it looked a bit like a white bird, edges flapping in the breeze. Her hair blew about her face too, and Tessa was reminded how young Charlotte was.

"From Nate, I suppose," said Charlotte. "His message for Jessamine." She brought it to Tessa, who tore the creamy parchment lengthwise in her eagerness to get it open.

Tessa glanced up. "It is from Nate," she confirmed. "He has agreed to meet Jessie in the usual place at sundown-" She gave a little gasp as, recognizing itself somehow as having been read, the note burst into quick, heatless flames, consuming itself until it was only a film of black ash on her fingers.

"That gives us only a little time," said Henry. "I Will go and tell Cyril to ready the carriage." He looked to Charlotte, as if for approval, but she only nodded without meeting his eyes. With a sigh Henry left the room-nearly bumping into Will, who was on his way back in, fol owed by a figure in a traveling cloak. For a moment Tessa wondered in confusion if it was a Silent Brother -until the visitor drew his hood back and she saw the familiar sandy-blond curling hair and green eyes.

"Gideon Lightwood?" she said in surprise.

"There." Charlotte slipped the map she was holding into her pocket. "The Institute Will not be Shadowhunterless."

Sophie got hastily to her feet-then froze, as if, outside the atmosphere of the training room, she was not sure what to do or say in front of the eldest Lightwood brother.

Gideon glanced around the room. As always his green eyes were calm, unruffled. Will, behind him, seemed to burn with bright energy by contrast, even when he was simply standing still. "You called on me?" Gideon said, and she realized that of course, looking at her, he was seeing Jessamine.

"And I am here, though I know not why, or what for."

"To train Sophie, ostensibly," said Charlotte. "And also to look after the Institute while we're gone. We need a Shadow-hunter of age to be present, and you qualify. In fact, it was Sophie who suggested you."

"And how long Will you be gone?"

"Two hours, three. Not all night."

"All right." Gideon began to unbutton his cloak. There was dust on his boots, and his hair looked as if he had been out in the cold wind, hatless. "My father would say it was good practice for when I run the place."

Will muttered something under his breath that sounded like "bloody cheek." He looked at Charlotte, who shook her head at him minutely.

"It may be that the Institute Will be yours one day," she said to Gideon quite mildly. "In any case, we're grateful for your assistance. The Institute is the responsibility of all Shadowhunters, after all. These are our dwel ing places- our Idris away from home."

Gideon turned to Sophie. "Are you ready to train?"

She nodded. They left the room together in a group, Gideon and Sophie turning right to make their way to the training room, the rest of them heading for the stairs. Bridget's mournful yowl was even louder out here, and Tessa heard Gideon say something to Sophie about it, and Sophie's soft voice in response, before they were too far away for her to hear them anymore.

It seemed natural to fal into step beside Jem as they went downstairs and through the nave of the cathedral. She was walking close enough to him that though they did not speak, she could feel the warmth of him against her side, the brush of his bare hand against hers as they stepped outside. Sunset was coming. The sky had begun to take on the bronze sheen that came just before twilight. Cyril was waiting on the front stairs, looking so much like Thomas that it hurt one's heart to look at him. He was carrying a long, thin dagger, which he handed off to Will without a word; Will took it and put it through his belt.

Charlotte turned and put her hand against Tessa's cheek. "We shall see you at the warehouse," she said. "You Will be perfectly safe, Tessa. And thank you, for doing this for us." Charlotte dropped her hand and went down the steps, Henry following her, and Will just after. Jem hesitated, just for a moment, and Tessa-remembering a night like this one, when he had run up the steps to bid her good-bye-pressed her fingers lightly against his wrist.

"Mizpah," she said.

She heard him suck in his breath. The Shadowhunters were getting into the carriage; he turned and kissed her quickly on the cheek, before spinning and running down the steps after the others; none of them seemed to have noticed, but Tessa put her hand to her face as Jem climbed, last, into the carriage and Henry made his way up to the driver's seat. The gates of the Institute swung open, and the carriage clattered out into the darkening afternoon.

"Shal we go, then, miss?" Cyril inquired. Despite how much he looked like Thomas, Tessa thought, he had a less diffident demeanor. He looked her directly in the eye when he spoke, and the corners of his mouth always seemed to be about to crinkle into a smile. She wondered if there was always one calmer and one more high-strung brother, like Gabriel and Gideon.

"Yes, I think we-" Tessa stopped suddenly, one foot about to descend the steps. It was ridiculous, she knew, and yet-she had taken off the clockwork angel to dress herself in Jessamine's clothes. She had not put it back on.

She couldn't wear it-Nate would recognize it immediately-but she had meant to put it into her pocket for luck, and she had forgotten. She hesitated now. It was more than sil y superstition; twice now the angel had literal y saved her life.

She turned. "I have forgotten something. Wait here for me, Cyril. I'll be only a moment."

The door to the Institute was still open; she charged back through it and up the stairs, through the hal s and into the corridor that led to Jessamine's room -where she froze.