Her mind also kept returning to Gavin. He was handsome, with a smile that made her think of sunshine and musical skill that made her soul soar. But he was the wrong social class, and Alice was engaged. It wasn’t proper for any woman in her position to be interested in him, and certainly not for a woman from a traditional family.

But she couldn’t have turned him out into the street after he had saved her life—twice. That wouldn’t have been proper, either.

Alice sat up and moved to her worktable, where she fiddled idly with a driveshaft and a pair of gears. Perhaps Norbert would consent to hire Gavin as a footman in his country home, where Alice could hear him anytime she wished. Then she scoffed to herself. Now she was just being foolish. She looked down at her hands and realized she had set the gears down and was toying with Glenda Teasdale’s calling card, the one Louisa had commented on earlier.

Alice didn’t need a change in her life. For once, everything was going where it should. But the entire affair with Aunt Edwina continued to puzzle her. Where had Aunt Edwina gone? Who had broken into her house and destroyed her laboratory? Why had she kidnapped Gavin? How had she survived the clockwork plague for so long? And why was that clockworker in the skull mask spying on her?

The Third Ward clearly dealt with questions of this sort. And so, although Alice Michaels definitely didn’t need a change in her life—most certainly did not—she scribbled a quick letter, folded it expertly into an envelope, and turned back to the calling card. Glenda hadn’t written an address on it. After a moment’s thought, Alice wrote Miss Glenda Teasdale, The Third Ward, √2.

“Kemp!” she called.

The door opened. “Madam?”

She handed him the letter. “Post this for me right away, please.”

“Of course, Madam.”

Alice climbed back into bed and surprised herself by instantly falling asleep.

“Baron Michaels wished to wake you earlier, but I wouldn’t hear of it,” Kemp said as Alice’s little automatons brought her a dress. “I have seen to his needs.”

“Thank you, Kemp.” Alice almost ordered Kemp out of the room while she dressed, but although Kemp was shaped like a man, he was only a machine. Still, she ordered him to turn his back.

“Madam, I must ask,” Kemp continued. “Why do you and Lord Michaels live in such frightful conditions? The Michaels family lineage is long and proud.”

“It’s what we can afford.” Alice slipped into the dress and waited while two little automatons fastened the buttons behind her. “Titles and wealth don’t always go together.”

Kemp gave a mechanical sniff. “Yes, Madam. I have taken the liberty of doing the shopping. Previous Madam still had a bit of petty cash money on account at a local bank, and I restocked the larder with something better than day-old bread and dried cheese. I think fresh fruit will do Lord Michaels some good.”

“That’s a relief, Kemp. Thank you.”

“And when you are finished with your toilette,” he said, “I will inform your callers that you are ready to receive them.”

Alice paused, a hairbrush in her hand. “Callers?”

“A Miss Glenda Teasdale and a Mr. Simon d’Arco arrived something over an hour ago. It’s the reason Lord Michaels wished to wake you.” Another sniff. “Mr. d’Arco appears to be of Italian extraction.”

But Alice wasn’t listening. She stuffed her hair into a serviceable bun and rushed down the stairs to the front room, where she found Gavin seated with Glenda Teasdale and Simon d’Arco. Simon, his dark eyes sparkling, was engaged in lively conversation with Gavin while Glenda, dressed in skirts and a puffy-sleeved blouse instead of trousers, sipped at a teacup.

Father was nowhere to be seen. The men rose when they caught sight of Alice. Gavin looked very fine; well-rested and dressed and combed. His white-blond hair shone in the gaslight. He caught her eye and smiled. She started to smile back, then caught herself.

“So good to see you, love,” Glenda said, taking Alice’s hand with Ad Hoc familiarity. “I was hoping you would contact us. We clearly have a great deal to discuss.”

Alice hesitated.Yesterday—or the day before—contacting the Third Ward had seemed a good idea. Now, with Glenda and Simon in her drawing room, it seemed less so.

“I prefer Miss Michaels,” she said carefully, “and I’m glad you came. My aunt—”

“Sorry to interrupt,” Simon said, doing so, “but this whole affair is a bit delicate, and we should probably talk about it at headquarters, where it’s safer.”

“Definitely.” Glenda, who hadn’t released Alice’s hand, was already towing Alice toward the stairs. “Shall we?”

“I can’t leave my father alone again,” Alice said. “It’s not right.”

“Your automaton can see to him,” Glenda breezed. “He’s only napping.”

It would be so easy to go with her. Then Alice thought of her father again, and of her new fiancé. She crossed her arms. “No. I can’t.”

Simon looked uncomfortable. “Please don’t put us in a difficult position, Miss Michaels. We speak with authority granted by the Crown, which gave us legal jurisdiction over anything to do with clockworkers, and this isn’t a secure place for a discussion. By authority of the Queen, we must insist. If you please, Miss Michaels.”

His tone was polite, but Alice heard the iron beneath it. She set her mouth and nodded once. “Fine.”

“Coming, Mr. Ennock?” Glenda asked.

Before Alice quite knew what was happening, the four of them were clattering up the steps to the second floor, Gavin with his fiddle case strapped to his back.

“Why are we going up here?” Alice asked.

“It’s how we came in, of course,” Glenda replied. She pushed open the half door at the end of the hall and stooped to crawl through, barely slowing down. Gavin shrugged and followed. Alice almost refused, but Simon d’Arco was standing right behind her, obviously expecting her to go, so she went. The little door led to a dusty airing cupboard that Alice hadn’t entered in years. A trapdoor opened onto the roof. Gavin turned to give her a hand out, and Simon came behind. A damp breeze teased at her hair, and a dizzying drop fell away to the street below. People bustled past on the narrow byway, looking tiny and unimportant. Even the noises they made were small. Alice prayed no one would look up and see her. But even as the thought crossed her mind, a boy pointed, and several people paused to stare upward. Alice turned her back. If word got back to Father that Alice was climbing about on the roof . . .

“Don’t worry. We’re not staying up here,” Glenda explained.

“We’re going in that?” Like the boy, Gavin pointed upward, his face shining with excitement.

Above them hovered a small dirigible, perhaps the size of a cottage. The dirigible’s gondola hung suspended by silken ropes, and the entire thing was tethered to one of the chimneys. Alice had been concentrating so hard on the people below that she hadn’t even noticed its presence. A wooden ladder extended itself toward them as she watched in startled amazement. Dirigibles she had seen, but never one hovering over her own house.

“There’s no space to land it on the street, which is why we’re on the roof. Up we go,” Simon said. “Does it make you nervous, Miss Michaels?”

It did, but the thought of appearing nervous in front of these people spurred Alice forward. “Not at all. Eyes down, Mr. Ennock. You, too, Mr. d’Arco.” She swarmed up the ladder. At the top, a thin, balding man with elaborate muttonchop whiskers gave her a hand into the gondola, then helped Glenda, Gavin, and Simon aboard. Simon folded up the ladder.

“You’re Pilot?” Gavin asked.

The thin man nodded and wordlessly turned to a small wheel Alice remembered was called a helm. Gavin expertly flicked the tether free, and the little propeller engines on the sides of the gondola whirred to life.

“Have you ever flown before, Miss Michaels?” Gavin asked.

“No,” Alice said as the city slid away below. Bitter-smelling coal smoke rose from a thousand chimneys, and a thousand people, horses, and automatons filled the streets. From up here, she could even see into the alleyways, where plague zombies shambled through the shadows, looking for garbage. A trio of well-dressed women in emerald dresses strolled the cobblestones, carrying signs that read DON’T THROW YOUR VOTE AWAY and THE AD HOC NEEDS YOU, unaware that only a few paces away a zombie lurked in the shadows, forced to hide from painful sunlight. Alleys emerged into side streets and joined larger streets, like tributaries joining rivers.

“It’s fascinating,” she breathed.

“It’s the most wonderful place to be,” Gavin told her, and she noticed how closely they were forced to stand in the confines of the tiny gondola. He looked happy, even thrilled, and that started a warm bit of happiness glowing inside Alice. She almost took his hand. He leaned over the side, and for a moment she thought he might leap over the edge and soar away.

“How do you know where to go?” Alice said. “Don’t you get lost?”

“It’s the same as on a ship, ma’am,” Pilot said. “We can use a chart with coordinates. We’re coming up on Buckingham Palace, for example, and that’s at fifty-one degrees, thirty minutes north, zero degrees, and eight minutes west. Of course, over London, it’s easier just to look down. You learn your way.”

“Does this ship go any higher?” Gavin asked of Pilot.

“Not with all these people in it,” the man grumbled.

Simon clapped Gavin on the back. “Lots of chances for flying in the Third Ward, Gav—Mr. Ennock.”

“You can call me Gavin,” he said. “I don’t mind.”

“I’m Simon. We’re very informal around the Ward, you see. It sets us apart from... everyone else.”

“What exactly is the Third Ward?”

“It’ll be easier to show you than tell you,” Glenda said.

As Pilot predicted, they passed almost directly over Buckingham Palace, official residence of Queen Victoria for twenty years now. Alice felt her own excitement and almost jumped up and down like a little girl at the sight. The Queen had ascended the throne when Alice was a baby, and like many English, Alice couldn’t remember or imagine a time without Queen Victoria and Prince Albert ruling the Empire. Alice looked down at the square, stately building surrounded by green gardens and wondered if the Queen were at this moment signing a proclamation or receiving an important dignitary or perhaps just sipping tea from a porcelain cup in a lavishly decorated hall. How wonderful and strange to glide above her.

Another section of the city passed beneath them, and then the airship passed over a stone wall surrounding another generous section of greenery, in the center of which lay a white mansion surrounded by outbuildings. The airship drifted gently downward to land with a soft bump on the lawn in front of the great house, and a pair of workmen dashed over to secure the ship. Everyone scrambled to disembark, and Glenda led them up the steps into the house.

The interior bustled with activity. Men dressed in business attire, servant livery, and ordinary workaday clothing hurried about on mysterious errands. There were even a number of women, though that shouldn’t have surprised Alice by now. Glenda guided them down a series of corridors, past rooms large and small. Alice and Gavin caught sight of several laboratories and workrooms. An enormous half-constructed automaton stood in one of them, while two men attached sheets of metal to it. Another laboratory sported bubbling beakers and winding copper tubes. A cage in the corner held half a dozen plague zombies who watched Alice with empty eyes as she passed. Yet another room was coated in fog, and a male figure appeared to be frozen in a block of ice. Alice couldn’t keep from staring.

“You’re very busy here,” she said breathlessly.

“They keep us occupied,” Simon replied with a smile.

“Where are we going?” Gavin asked.

“Here.” Glenda knocked once on a closed door, then ushered Gavin and Alice into an office, or perhaps it was a library. Floor-to-ceiling shelves held books, maps, scrolls, and strange instruments Alice couldn’t identify. Tall windows looked out over the grounds, and thick Persian rugs covered the floors. The center of the room was dominated by a large desk piled with neat stacks of papers. An odd combination telegraph machine and typewriter occupied one corner. Behind the desk sat a tall woman with black hair pulled into a French twist. She wore a man’s military uniform, crisp and blue, with gold epaulets. It was specially cut to expose her left arm, which was entirely mechanical. Alice noted with a start that it had six fingers. An elaborate brass-rimmed monocle covered the woman’s left eye, and a small sign on her desk read LIEUTENANT SUSAN PHIPPS.

“The ones from our report, Lieutenant,” Glenda said. “Alice Michaels, daughter of Arthur, Baron Michaels, and Gavin Ennock from Boston.”

“Thank you, Glenda,” said Lieutenant Phipps. Her voice was quick and sharp as a pair of scissors. “Excellent work, both of you. Simon, please meet us down in the sound laboratory in ten minutes.”

Glenda and Simon withdrew. Phipps pointed to a pair of wooden chairs across from her desk. “Sit. Please.”

Alice and Gavin sat. Gavin looked solemn but at ease, and Alice supposed that as an airman, he was used to a military chain of command. For her own part, Alice found Lieutenant Phipps more than a little intimidating, and she forced herself to sit with her hands in her lap, though she wanted to twist at her skirt as she had as a child. She tried not to stare at Phipps, this woman who dressed and spoke like a man, and broke so many traditional rules. But of course, she was part of this Third Ward, and the Ward clearly welcomed Ad Hoc women.

Phipps set a packet of papers aside and pulled the telegraph-typewriting machine toward them on its rolling stand. The machine had a recording horn on it. Phipps spun a crank on the side and fed a long scroll of paper into the typewriter’s platen. “I’m sure you’re wondering what’s going on and why you’re here, so I’ll come straight to the point. First, I need to hear from you everything that happened at that country house. Don’t leave anything out. Mr. Ennock, you start. I understand you used to play fiddle in Hyde Park.”

Gavin told his story. As he spoke, the machine sprang to life. The typewriter clacked, and Gavin’s words skittered across the scroll. Gavin paused in surprise. Alice leaned forward. Her fingers itched to take the side panels off the machine so she could examine how the insides worked, discover how many memory wheels it took to translate sound into written words. Phipps pressed a switch on the machine and it stopped.

“Ignore the transcription, Mr. Ennock,” she said. “It’s for our records. Continue.”

He did. When he finished, Phipps had Alice tell her story as well. The machine wrote it all down. Phipps tore the scroll off, rolled it up, and put it in a drawer.

“Is that all?” Alice asked. “Are we free to go?”

“One more point.” Phipps steepled her fingers, brass and steel on flesh. “I need you both to listen carefully. The Third Ward is a busy and chronically understaffed organization, and we’re crying for talent. Based on what I’ve learned about the two of you over the last several days, I’m prepared to offer you positions as agents with us. The salary starts at five hundred pounds per annum, and room and board at cost, if you desire it.”

Alice gaped. It was the last thing she’d been expecting to hear. She exchanged a quick glance with Gavin and understood that he felt the same way. “I don’t understand,” she said slowly. “What exactly does the Third Ward—”

“Did you say five hundred pounds?” Gavin interrupted.

“I did,” answered Phipps. “And before you answer, let me show you what it means to be an agent of the Third Ward.”

She strode for the door without looking behind. Alice and Gavin rushed to catch her up. Phipps marched ahead of them, her bearing straight as a tin soldier’s.

“You’ve probably guessed that I’ve already looked into your backgrounds,” she said. “Both of you are quick, intelligent thinkers, and you have talents we need. And”—she lifted a metal finger before either of them could interrupt—“I’m going to explain what we do as we walk, so listen and look.”

They passed a gymnasium where groups of men and women sparred with fists and feet. “The Third Ward was established during the reign of King George the Fourth by the Duke of Wellington,” Phipps began.

“The Iron Duke,” Alice said.

“Yes, and if you interrupt again, this will take longer,” Phipps admonished. “Wellington defeated Napoleon at Waterloo, but only just. The French had access to horrifying machines of war created by three clockworkers Napoleon had... persuaded to work for him. Wellington decided then and there that the best thing he could do for England was to gather up these madmen and -women and keep their inventions under control before one of them managed to destroy the country—or the world. He established the Third Ward to do that.”

“His Majesty George the Fourth was amenable to this?” Alice said. “I’m sorry to interrupt, but that doesn’t sound like him. King George wasn’t known for—well, he was more of...”

“An insular sybarite? A man who found the contents of his bedchamber more important than the contents of his country? Yes. That was why Wellington kept the Ward a secret. He diverted Crown funds for it and kept it hidden from His Majesty until William the Fourth took the throne in 1830.”

“William was Victoria’s uncle, right?” Gavin said.

Phipps gave him a curt nod. “By then, the tradition of secrecy was well established, so even though the Crown supports the Ward, we don’t officially exist. Too many people would be unhappy if they were aware of what we were doing right under their noses.”

“What are we—you—doing?” Alice asked.

“I told you—we gather clockworkers. We give them a supervised place to work, and we harvest their inventions to serve the Empire. Why do you think England rules most of the known world?”

“And what about China?” Alice couldn’t help asking. Phipps’s snappy tone set her a bit on edge.

“They have their own system for dealing with clockworkers,” Phipps acknowledged. “And it’s why they’ve managed to hold their own against us.”

“The revolt over the Treaty of Nanking,” Gavin said. “And Lord Elgin’s fight with Emperor Xianfeng.”

Phipps looked at him. “Yes. How does a cabin boy from a shipping dirigible know about that?”

“I’m young, but I’m not stupid,” Gavin said airily, and Alice suppressed a smile.

“Quite.” Phipps took them into a small, square room and pulled shut an iron gate. “Other countries look at clockworkers and see a threat. They think of plague zombies carrying disease, and never mind that clockworkers don’t communicate the clockwork plague. And they see terrifying technology, of course. So they shun clockworkers or kill them.”

She turned a crank and flipped a switch on the wall of the room. The floor gave a sharp jerk, and the entire chamber descended. Alice squeaked and grabbed Gavin’s elbow.

“It’s called a lift,” Phipps said. “It’s perfectly safe. One of our clockworkers modified the original design from America. It runs on electricity.”

“Oh,” Alice said. “I’d like to examine it sometime.”

“If you come work for us.” Two floors passed by them, followed by a thick layer of stone.

“Why do clockworker inventions remain so rare?” Gavin asked. “I mean, we saw that giant automaton upstairs, and you mentioned the war machines at Waterloo. Why doesn’t the Crown build more and more of them?”

“We can’t,” Phipps told him. “A few inventions can be re-created, certainly. Babbage engines. Electric lights. Hardened glass. Designs for dirigibles. But the vast majority of clockworker inventions, especially the ones with any sort of power source, are so complicated, so complex, that no one can re-create them. Not even if the clockworker manages to draw extended diagrams.”

“As my aunt has done?” Alice asked.

“Exactly as your aunt has done. That’s one of the reasons why we’re interested in you, Miss Michaels. As far as we know, you’re the only person able to follow a clockworker’s thinking well enough to assemble a clockworker’s inventions. Your cat Click, for example, and that automated valet.”

“But I don’t understand them,” Alice said. “I just assemble them.”

“That’s a singular ability, Miss Michaels. With few exceptions, only a clockworker can create the pieces of advanced technology we need to keep the Empire running, and once something has been created, only a clockworker can maintain or re-create it. Perhaps you can assemble these inventions because your family has been touched by the clockwork plague so often. Or perhaps you’re some sort of clockworker yourself. A demi-clockworker, if you will.”

All the strength drained out of Alice’s body, and the blood left her face. Her voice dropped to a whisper. “I hadn’t considered that.”

“Don’t go all fussy,” Phipps growled. “If you were going to die of clockwork plague or infect someone else, you would have done it long ago. I don’t put up with the idea that women are the weaker sex or that females are particularly prone to hysterics, so if you’re going to prove me wrong, do it elsewhere.”

The words stung like a slap, and Alice came to herself. “You may have researched my background, Lieutenant,” she snapped, “but you know nothing of me, so you may keep your comments to yourself, thank you.”

Phipps gave her a curt nod, and Alice wondered if that had been some sort of test. “At any rate, America is starting to see the value of clockworkers, but it remains too deeply divided over slavery and economic issues to make proper use of them. India treats clockworkers as untouchables, of course, and the Africans and Muslims stone them to death. Ever since we’ve colonized these places, the Ward has been able to snatch clockworkers away for our—the Crown’s—use. China, as I said, has its own clockworkers, and we seem to be locked in a constant struggle to stay abreast of them.”

“We invent something; they invent something a bit better; we have to invent something a bit better than that,” Alice said.

“Exactly. Just recently, a Chinese clockworker bred an entire new species of silkworm. It produced thread that could be woven into a lightweight cloth that blends into nearly any surrounding, much like a chameleon. The military implications were staggering.”

“Not to mention what a smuggler could use it for,” Gavin pointed out.

“An airman would think of that,” Phipps said. “Fortunately for us, one of our own clockworkers created a special lens that converts heat—he calls it infrared energy—into visible light. He created several, in fact, and we handed them out to the army, which rendered the chameleon cloth much less useful.” She tapped her own monocle. “They’re also quite nice for seeing in the dark.”

The lift came to a stop, and Phipps slid the iron gate open. A chilly stone corridor greeted them. Electric lights provided a steady glow, though the place smelled of damp.

“What’s this place?” Alice asked.

“The high-powered floor.”

Phipps took them out of the lift, and Alice abruptly realized she was still holding Gavin’s elbow. Her face grew hot and she let go. Gavin didn’t seem to notice, or pretended not to.

“This is where we keep the most powerful clockworkers and their technology,” Phipps said. “This is what our agents live to find—and protect. It’s what holds the British Empire together.”

Alice was expecting even more wonders than she’d seen upstairs, but they only passed a series of side corridors and heavy, closed doors. Behind one of them, however, she heard a muffled explosion and what might have been a scream.

“What’s that?” Gavin asked. He was pointing down a short corridor that ended in a round steel door that looked to be ten or twelve feet in diameter. Flanking it were four guards armed with wicked-looking rifles Alice couldn’t begin to identify. They certainly didn’t fire bullets.

“That’s the Doomsday Vault,” Phipps said. “Sometimes a clockworker will create something so terrifying or dangerous that using it would be unthinkable, even in dire need. We lock all such inventions in the Vault, where no one can touch them. There’s enough power beyond that door to demolish the world a dozen times over.”

“Why not simply destroy such devices?” Alice asked, aghast.

“Believe me, Miss Michaels, we’ve had many discussions about that over the decades. Some devices are too dangerous to destroy. Other devices might turn out to be useful later. Another clockworker might invent a safeguard, for example, that makes the original device highly useful. In the end, Her Majesty decreed that we keep everything, just in case.”

“How do they create these inventions, Lieutenant?” Alice asked. “And how far can they go?”

“That’s the question that gives me nightmares, Miss Michaels. We used to think that clockworkers were bound by the laws of physics, and they could do something only if it were physically possible and they had enough money and the right equipment. But now the clockworkers are discovering that the boundaries of these physical laws are . . . porous. I hear them use phrases such as gravity sinkhole and extra-temporal commutation. I think that last term has something to do with traveling in time. I’ve had two—two—clockworkers tell me that matter and energy are the same thing, and another one said he could see entire universes that occupy the same space as this one. I thought he had reached the complete lunatic point in his illness, but then he turned up with three parallel versions of himself, and it was only with great difficulty that we persuaded him to send them back. The world is very lucky that they need extensive and expensive equipment to create their most powerful inventions, or Earth would have been destroyed long ago. They create with great glee and don’t think about the repercussions, which is why the Third Ward has to search them out and bring them here, where we can keep their work in check.”

She took them to a particular door, selected a strange-looking key from a ring on her belt, and tapped it near the lock. The key rang—it was actually a tuning fork.

“C-sharp,” Gavin said.

“I wouldn’t know,” Phipps said. The lock clicked, and she pushed the door open. “This is the sound laboratory, and we need you here, Mr. Ennock.”

“Gavin!” Simon d’Arco rose from a marble worktable. “Glad you arrived. And nice to see you again, Miss Michaels.”

“It’s been only a few minutes, Mr. d’Arco,” Alice said.

“‘Simon,’ please. I said we’re very informal in the Ward.”

“Do you call the lieutenant ‘Susan’?” Alice asked, genuinely curious.

“No,” Phipps said.

“And this”—Simon gestured to another man—“is Gabriel Stark, but he prefers to be known as Doctor Clef.”

A shortish, balding man in coveralls, goggles, and a stained white coat looked up from the strange object he was working on. The object appeared to be a wire framework, but it twisted Alice’s eye. The lines of the cube came together... wrong. The more she looked at it, the more the front of the lattice seemed to fade into the back, or maybe the back was coming into the front. The man pushed his goggles onto his high forehead, revealing watery blue eyes set into a round face. “Good day,” he said in the broad, loopy tones of a north German.

“What is that thing?” Alice asked.

“Do you like it?” Dr. Clef said. “It is a cube, and it is quite impossible. Watch this.” He reached for a machine mounted on his desk. A wire led from the machine to the Impossible Cube, and when Dr. Clef spun a crank on the machine, the wires in the cube sparked and glowed blue. As Alice watched, the cube trembled, then rose a good inch above the table.

“It can fly!” Gavin gasped.

“Good heavens!” Alice said. “Is it a magician’s trick?”

“No, no.” Dr. Clef stopped cranking, and the cube dropped back to the table. “It is an alloy of my own design. When the electricity goes through the metal, it ignores gravity a little. It allows the Impossible Cube to do what it must do.”

“And what is that?” Alice asked.

Dr. Clef blinked at her. “How can I know? It is not yet finished.”

“It can fly,” Gavin muttered. “Fly!”

“Doctor Clef is one of our more prolific clockworkers,” Simon told them. “His work is currently at a delicate stage, and he didn’t want to stop, so—”

“Go on, go on.” Dr. Clef made shooing motions with his screwdriver. “Do not mind me. I make no sound.”

“So come in,” Simon said. “The laboratory awaits.”

The sound laboratory was a brightly lit stone room filled with equipment Alice didn’t recognize, some of it small, some of it large, and Alice’s fingers itched to take every piece apart and examine them from the inside. One wall was taken up by a variety of musical instruments—harp, drum, piano, violin, cello, flute, bugle, trumpet, and more. Another wall was filled with bookcases and books. Simon led Gavin to the instrument wall.

“Do you know why we’re excited to have you, Gavin?” he asked.

Gavin shook his head. He was still staring at the Impossible Cube.

“We suspect you have a musical talent of a type that appears perhaps once a generation,” Simon explained. “Or even less often.”

“How did you know he has such a musical talent?” Alice interrupted.

“Our agents heard him play in Hyde Park, and we suspected,” Phipps said. “But before we could move to find out more, he inexplicably vanished. We couldn’t find him anywhere. You can imagine our reaction when Agent Teasdale got your letter and he turned up at your home, Miss Michaels, especially since we’ve been investigating your aunt.”

“Have you?” Alice said in a chilly tone.

“Of course. She falls under our jurisdiction. We learned of your aunt’s condition several weeks ago and sent agents to investigate. When our people arrived, they found her house in a difficult state. A trap near her front door instantly killed one of my people. His name was Franklin Mayweather, and he had a wife and two children.”

Alice remembered the puddle of dried blood on the floor. Guilt stabbed her stomach, even though she’d had nothing to do with the trap or Franklin Mayweather’s death.

“My people tried to capture the woman Edwina,” Phipps continued, “but she eluded them and vanished. Her house was heavily trapped, and after some investigation, they decided the place was too dangerous for further exploration, so they left.”

“Then who demolished her laboratory?” Alice asked.

“I couldn’t say. However, apprehending Edwina is still a high priority. She has already killed Franklin Mayweather, and we need to stop her before someone else pays the same price. In addition, the clockworker who controlled those plague zombies and wreaked havoc the night of the Greenfellow ball is still at large, and we have a number of cases on the Continent we’re overseeing. In other words, we need all the agents we can lay hands on.”

“And musical talents such as Gavin’s are useful in the extreme.” Simon sat at the piano and played a single key. “What note is this?”

“B,” Gavin said, tearing his gaze away from Dr. Clef’s cube. “I have perfect pitch. You don’t need to test that.”

“Indulge me.” Simon played several notes, all of which Gavin named perfectly. Then he played chords, and Gavin named those as well. Occasionally he played one chord with one hand and another chord with the other, which Gavin helpfully pointed out. “Good, good.”

“This young man is pleasing to me,” Dr. Clef called from his worktable. “How well do you remember the music?”

“I learn fast,” Gavin said, taking out his fiddle and tuning it quickly. Alice leaned forward on her stool.

“How fast?” Dr. Clef asked.

“I’m running the tests, Doctor Clef,” Simon said. “I thought you had work to do.”

“Yes, yes, yes.” Dr. Clef bent studiously over his cube, though Alice could see him peering at Gavin, despite his goggles.

“Play something,” Gavin said.

Simon played in a minor key. Gavin listened through one verse and one chorus. Simon stopped playing, and Gavin played it through perfectly. Simon joined back in again, and Gavin played harmony. They played other songs back and forth, songs Alice couldn’t identify. Gavin’s fiddle swooped and spun, though every note echoed off hard stone. Dr. Clef gave up all pretense of working and listened. Alice heard a quiet longing in the music, a wish for every note to fly free, and it brought a quiet tear to one eye.

“That was perfect,” Simon breathed. “Can you sing, Gavin?”

“Yes.”

“Sing something for me, then. Your favorite song.”

“ ‘The Wraggle Taggle Gypsies,’ ” Gavin said. He raised his fiddle for accompaniment and sang.

Alice stared. She had never heard Gavin sing. His light, clear voice arrested her. His white-blond hair shone in the bright electric light, and his lithe body moved with the fiddle. He played and sang with his entire soul, and Alice wanted to get up and dance.

Gavin’s voice and fiddle tugged at Alice. They sang of adventure, of new places, of casting off rules and conventions. In that moment, she would have followed Gavin anywhere. Dr. Clef had abandoned his work and was now sitting at Gavin’s feet like a small child. Gavin’s blue eyes met Alice’s brown ones, and she couldn’t look away. She didn’t want to.

The song ended. Dr. Clef jerked as if he had been slapped awake. Simon applauded. Phipps stood nearby with her arms crossed, expression unreadable. Alice spun sideways on the stool, face flushed.

“Marvelous!” Simon said. “Worthy of a concert hall.”

“Not the first time someone has told me that, actually,” Gavin said with a wry smile. He tried to catch Alice’s eye, but she didn’t dare meet that gaze. “You still haven’t explained why this is worth something to you.”

Dr. Clef crept back to his table and set back to work, one eye still on Gavin.

“One last question before I answer.” Simon turned back to the piano. “What kind of interval is this?”

He played it, and Dr. Clef yelled. Alice twisted on her stool in alarm. The clockworker clapped both hands over his ears and yelled and yelled. Lieutenant Phipps was instantly by his side. She touched his cheek with her mechanical hand, and he calmed.

“I’m sorry, Doctor Clef,” Simon said. “I forgot you were in the room.”

“What was that all about?” Alice demanded. She was still half-ready to run for the door.

Gavin grimaced. “I don’t know the name of the interval, but no song I know uses it.”

“A tritone,” Alice put in. “The Devil’s Interval. The one you asked me to play during the zombie attack.”

“Exactly.” Simon closed the piano lid. “And it all comes back to clockworkers. They love music. They can even be entranced or hypnotized by an exceedingly well-played song, the more complicated the better, as Doctor Clef demonstrated. So you can see why someone who can sing and play like you do, Gavin, would be a tremendous asset to a group that collects clockworkers.”

“Why tritones?” Alice asked. “We used one during the zombie attack, but no one would explain why it worked.”

“They are horrible,” Dr. Clef muttered. “Ungeheurlich.”

“Most clockworkers experience actual pain when they hear a tritone,” Simon explained. “The instrument you repaired during the zombie attack was designed to play music especially loudly, and you saw the impact a loud tritone had on that clockworker.”

“In addition,” Phipps added, “it’s important to understand that all musical intervals can be expressed as numbers, determined by the frequency ratio.”

“Frequency ratio?” Gavin said.

“In simple terms,” Simon said, “when an object such as a string of a certain length vibrates at a certain speed to create a certain sound, it produces a certain number of cycles—a measurement of sonic energy. If you compare that string with another string vibrating at a different speed, you get a ratio. Perhaps one string produces three cycles each time the other produces two cycles, giving us a ratio of three to two. That particular ratio, incidentally, makes the sound of a perfect fifth. Two strings vibrating at a ratio of two to one will give us an octave.”

“I don’t understand what this has to do with clockworkers finding tritones painful,” Alice said.

“The frequency ratio of a perfect tritone does not exist,” Simon said. “In mathematical terms, the ratio of a tritone is one to the square root of two.” Dr. Clef shuddered at his table.

“The square root of two?” Alice repeated. “But that can’t exist.”

“That’s what I just said. The square root of two is an irrational number. On the one hand, it must exist—we can see it in a right triangle. We can hear it in the frequency ratio of a tritone. But on the other hand, no two identical rational numbers will multiply together to make two. The square root of two can’t exist, and yet it does. Irrational. We think this is why tritones bother clockworkers so much. They sense aspects of the universe that normal people can’t, and the paradox created by that irrational frequency ratio causes them distress.”

“And that’s why the symbol of the Third Ward is the square root of two,” Phipps said. “We shouldn’t exist, but we do. Which brings me to our next point. Gavin Ennock, you have a musical talent that would be very useful to the Third Ward. I would like to officially offer you a position as an agent. Will you accept?”

“Yes,” Gavin said instantly.

Phipps nodded, though her expression didn’t change. “And Alice Michaels, you have a talent for assembling and using clockworker technology, one never before seen. This would also be extremely useful to the Third Ward. Will you accept a position as an agent?”

Alice looked at Gavin’s expectant face, then at Phipps’s impassive one.

“No,” she said.

“No?” Gavin said. “Al—Miss Michaels! Why not?”

“I don’t wish to discuss it, Mr. Ennock,” Alice replied primly. “But I do wish to leave. Now.”

Phipps’s expression remained neutral. “If you like. But first I have to perform a quick procedure.”

She drew a strange-looking pistol, and Alice pulled back with a hiss. “What on earth?”

“This is not a weapon, Miss Michaels.” Phipps unwound a cable from the stock and plugged it into a receptacle in her own forearm. A high-pitched whine grated in Alice’s ears just as Phipps pulled the trigger, and Alice was half-blinded by a dazzling pattern of color. She rubbed at her eyes, trying to regain her vision.

“What was that?” she demanded.

“Another clockworker invention,” Phipps said. “As I understand it, the light patterns disrupt the connections between the portion of your brain that stores recent memory and the portion that controls speech. In other words, you won’t be able to talk about anything that has happened in the last two hours, more or less. It’s standard practice for all those who see our installation but aren’t part of the Third Ward. Simon will see you out. Gavin will, of course, stay here to begin his training immediately.”

And she turned her back on Alice to talk to Gavin. Alice left the room, leaving Simon to scramble after her. She kept an icy silence all the way up the elevator, out the main doors, and to the main gates, where Simon hailed a cab for her.

“Can you tell me why, Miss Michaels?” he asked, dark eyes almost pleading.

“I’m late for luncheon with my fiancé, Mr. d’Arco,” Alice said. “Good day.”

And she was gone.