Behind the table stood Henry, and beside him, Charlotte. Henry was showing his wife something he held in his hand—a copper wheel, perhaps a gear—and was speaking to her in a low voice. He wore a loose canvas shirt over his clothes, like a fisherman’s smock, and it was smeared with dirt and dark fluid. Still, what struck Tessa most about him was the assurance with which he spoke to Charlotte. There was none of his usual diffidence. He sounded confident and direct, and his hazel eyes, when he raised them to look at Tessa, were clear and steady.

“Miss Gray! So Sophie showed you the way down here, did she? Very good of her.”

“Why, yes, she—,” Tessa began, glancing behind her, but Sophie was not there. She must have turned at the door and gone soundlessly back up the stairs. Tessa felt foolish for not having noticed. “She did,” she finished. “She said that you wanted to see me?”

“Indeed,” Henry said. “We could use your help with something. Could you come over here for a moment?”

He gestured for her to join him and Charlotte by the table. As Tessa approached, she saw that Charlotte’s face was white and pinched, her brown eyes shadowed. She looked at Tessa, bit her lip, and glanced down toward the table, where the heaped fabric—moved.

Tessa blinked. Had she imagined it? But no, there had been a flicker of movement—and now that she was closer, she saw that what was on the table was not so much a pile of fabric as fabric covering something—something approximately the size and shape of a human body. She stopped in her tracks, as Henry reached out, took hold of a corner of the fabric, and drew it away, revealing what lay beneath.

Tessa, feeling suddenly dizzy, reached to grasp the edge of the table. “Miranda.”

The dead girl lay on her back on the table, her arms flung out to either side, her dull brown hair straggling down around her shoulders. The eyes that had so unnerved Tessa were gone. Now there were hollow black sockets in her white face. Her cheap dress had been cut open down the front, baring her chest. Tessa winced, looked away—and then looked back quickly, in disbelief. For there was no naked flesh, and no blood, despite the fact that Miranda’s chest had been sliced open down the front, her skin peeled back on either side like the skin of an orange. Beneath the grotesque mutilation gleamed the brightness of—metal?

Tessa moved forward until she was standing across from Henry at the table where Miranda lay. Where there should have been blood, torn flesh, and mutilation, there were only the two sheets of white skin folded back, and beneath them a carapace of metal. Sheets of copper, intricately fitted together, made up her chest, flowing smoothly down into a jointed cage of copper and flexible brass that was Miranda’s waist. A square of copper, about the size of Tessa’s palm, was missing from the center of the dead girl’s chest, revealing a hollow space.

“Tessa.” Charlotte’s voice was soft but insistent. “Will and Jem found this—this body in the house where you were kept. The house was completely empty except for her; she’d been left in a room, alone.”

Tessa, still staring in fascination, nodded. “Miranda. The Sisters’ maidservant.”

“Do you know anything about her? Who she might be? Her history?”

“No. No. I thought … I mean, she hardly ever spoke, and then she only repeated things the Sisters had said.”

Henry hooked a finger into Miranda’s lower lip and pulled her mouth open. “She has a rudimentary metal tongue, but her mouth was never really constructed for speech, or for consuming food. She has no gullet, and I would guess no stomach. Her mouth ends in a sheet of metal behind her teeth.” He turned her head from side to side, his eyes narrowing.

“But what is she?” Tessa asked. “A sort of Downworlder, or demon?”

“No.” Henry let go of Miranda’s jaw. “She is not precisely a living creature at all. She is an automaton. A mechanical creature, made to move and appear as a human being moves and appears. Leonardo da Vinci designed one. You can find it in his drawings—a mechanical creature that could sit up, walk, and turn its head. He was the first to suggest that human beings are only complex machines, that our insides are like cogs and pistons and cams made of muscle and flesh. So why could they not be replaced with copper and iron? Why couldn’t you build a person? But this. Jaquet Droz and Maillardet could never have dreamed of this. A true biomechanical automaton, self-moving, self-directing, wrapped in human flesh.” His eyes shone. “It’s beautiful.”

“Henry.” Charlotte’s voice was tight. “That flesh you’re admiring. It came from somewhere.”

Henry passed the back of his hand across his forehead, the light dying out of his eyes. “Yes—those bodies in the cellar.”

“The Silent Brothers have examined them. Most are missing organs—hearts, livers. Some are missing bones and cartilage, even hair. We cannot but assume the Dark Sisters were harvesting these bodies for parts to create their mechanical creatures. Creatures like Miranda.”

“And the coachman,” Tessa said. “I think he was one as well. But why would anyone do such a thing?”

“There is more,” Charlotte said. “The mechanical tools in the Dark Sisters’ cellar were manufactured by Mortmain and Company. The company your brother worked for.”

“Mortmain!” Tessa tore her gaze from the girl on the table. “You went to see him, didn’t you? What did he say about Nate?”

For a moment Charlotte hesitated, glancing at Henry. Tessa knew that glance. It was the sort of glance people gave each other when they were preparing to engage in a joint falsehood. The sort of look she and Nathaniel had given each other, once, when they’d been concealing something from Aunt Harriet.

“You’re hiding something from me,” she said. “Where’s my brother? What does Mortmain know?”

Charlotte sighed. “Mortmain is deeply involved in the occult underworld. He’s a member of the Pandemonium Club, which seems to be run by Downworlders.”

“But what has that to do with my brother?”

“Your brother found out about the club and was fascinated by it. He went to work for a vampire named de Quincey. A very influential Downworlder. De Quincey is in fact the head of the Pandemonium Club.” Charlotte sounded bitterly disgusted. “There is a title to go with the job, it seems.”

Feeling suddenly dizzy, Tessa braced her hand against the edge of the table. “The Magister?”

Charlotte looked at Henry, who had his hand inside the creature’s chest panel. He reached in and drew something out—a human heart, red and fleshy, but hard and shiny-looking as if it had been lacquered. It had been bound around with copper and silver wires. Every few moments it would give a listless thump. Somehow it was still beating. “Would you like to hold it?” he asked Tessa. “You’d have to be careful. These copper tubes wind throughout the creature’s body, carrying oil and other flammable liquids. I have yet to identify them all.”

Tessa shook her head.

“Very well.” Henry looked disappointed. “There was something I wished you to see. If you’ll simply look here—” He turned the heart carefully in his long fingers, revealing a flat metal panel on the opposite side of it. The panel had been etched with a seal—a large Q, a small D inside it.

“De Quincey’s mark,” said Charlotte. She looked bleak. “I’ve seen it before, on correspondence from him. He’s always been an ally of the Clave, or so I thought. He was there at the Accords when they were signed. He’s a powerful man. He controls all the Night Children in the western part of the city. Mortmain says that de Quincey bought mechanical parts from him, and this would seem to bear that out. It looks as if you weren’t the only thing in the Dark Sisters’ house that was being prepared for the Magister’s use. These clockwork creatures were as well.”

“If this vampire is the Magister,” Tessa said slowly, “then he is the one who had the Dark Sisters capture me, and he is the one who forced Nate to write me that letter. He must know where my brother is.”

Charlotte almost smiled. “You are single-minded, aren’t you.”

Tessa’s voice was hard. “Don’t imagine that I don’t want to know what the Magister wants with me. Why he had me captured and trained. How on earth he knew I had my—my ability. And don’t think I wouldn’t want revenge if I could have it.” She took a shuddering breath. “But my brother is all I have. I must find him.”

“We will find him, Tessa,” Charlotte said. “Somehow all of this—the Dark Sisters, your brother, your own ability, and de Quincey’s involvement—fits together like a puzzle. We simply haven’t found all the missing bits of it yet.”

“I must say, I hope we find them soon,” Henry said, casting a sad glance at the body on the table. “What could a vampire want with a lot of half-mechanical people? None of this makes any sense.”

“Not yet,” said Charlotte, and she set her small chin. “But it will.”

Henry remained in his laboratory even after Charlotte had announced that it was past time for them to return upstairs for supper. Insisting that he would be along in five minutes, he waved them off absently as Charlotte shook her head.

“Henry’s laboratory—I’ve never seen anything like it,” Tessa said to Charlotte when they were halfway up the stairs. She was already out of breath, though Charlotte was moving with a steady, purposeful gait and looked as if she would never tire.

“Yes,” Charlotte replied a little sadly. “Henry would spend all day and all night there if I allowed it.”

If I allowed it. The words surprised Tessa. It was the husband, wasn’t it, who decided what was and was not allowed, and how his home should be run? The wife’s duty was simply to carry out his wishes, and to provide him with a calm and stable refuge from the chaos of the world. A place he might retreat. But the Institute was hardly that. It was part home, part boarding school, and part battle station. And whoever might be in charge of it, it clearly wasn’t Henry.

With an exclamation of surprise, Charlotte stopped short on the step above Tessa. “Jessamine! What on earth’s the matter?”

Tessa looked up. Jessamine stood at the head of the stairs, framed in the open doorway. She still wore her day clothes, though her hair, now in elaborate ringlets, had clearly been arranged for evening, no doubt by the ever-patient Sophie. There was an immense scowl on her face.

“It’s Will,” she said. “He’s being absolutely ridiculous in the dining room.”

Charlotte looked puzzled. “How is this different from his being totally ridiculous in the library or the weapons room or any of the other places he’s usually ridiculous?”

“Because,” Jessamine said, as if this should be obvious, “we have to eat in the dining room.” She turned and flounced off down the hallway, glancing back over her shoulder to make sure that Tessa and Charlotte were following her.