Plague zombies in various stages of deterioration filled the byway. They were—had been—men and women, boys and girls. It looked to be every zombie in London. They limped and hobbled and dragged themselves through the mist, skin sloughing off their muscles, open sores festering in the dim gaslight. The hackney horse snorted in fear. Terrified, Alice pressed herself against the wall. A tiny whimper died in her throat. It was every nightmare she’d ever had come to life. The plague had taken her mother, brother, and fiancé. Now it was lurching toward her in a crowd of mottled, oozing flesh.

Screams from frightened horses and shouts of panicked people filled the air. Alice stayed perfectly still, trying to remain as inconspicuous as a woman in a ball gown could. Her breath came in quick, short pants as she tried to overcome her fear and make sense of what she saw in the street. The crowd of zombies oozed around night-delivery carts, rocking them, shoving at them—they were working together. It was impossible. Plague zombies suffered from an advanced case of the clockwork plague, a disease that attacked both body and brain. It separated skin from muscle and opened up holes in the dermis. It attacked neural tissue, creating dementia, palsy, and paralysis. Nine times out of ten, it killed. The plague was highly contagious, but only after initial contraction, when the victim was asymptomatic, and toward the end, when the victim looked more monster than human. At this stage, the victim’s eyes also became sensitive to daylight, forcing a nocturnal existence that might last for a year before death finally claimed them, though most died of starvation or exposure long before then. Ironically, it was the contagious aspect of the disease that allowed plague zombies to exist within London—the police and other authorities were afraid to get too close for fear of contracting the illness themselves.

But for their contagious nature, zombies were usually harmless scavengers who looked more frightening than they actually were. They didn’t have the mental capacity to work together in their final months. Yet this mob was doing exactly that.

There was a crash, and the street flooded with ale as the zombies tipped over a beer delivery van. Drovers scrambled away and fled, abandoning lorries and teams of horses alike.

And then she heard the music—low, eerie music that reminded her of a flute or an oboe. Intricate and strange, it wove in and through the crowd of zombies. She remembered hearing it earlier, as she left the dance. It chilled her blood. Alice tracked the sound to a figure standing in the middle of the plague zombie crowd. The figure wore a long brown coat with tarnished silver buttons, and a battered top hat. A white mask covered the upper half of its face. It grinned almost wider than any human should be able to grin. In its hands, the figure held a strange device that looked a bit like a set of bagpipes, but without the mouthpiece, and with a number of strange and tiny machines attached. The figure grinned and grinned, white teeth shining in the dim light. Its fingers moved across the device, and the music grew louder. The zombies jerked in unison and tipped over another truck.

“A clockworker,” Alice whispered with understanding.

Every so often, perhaps one time in a hundred thousand, the plague gave even as it took. Instead of destroying the victim’s brain, the disease made it work with a wondrous efficiency. Mathematics, physics, biology, chemistry—even some forms of art—became mere toys to these rare and particular plague victims. They created amazing, impossible inventions. Every automaton in existence, for example, owed its mechanical brain to Charles Babbage catching the plague and almost overnight perfecting the analytical engine. Jean-Pierre Blanchard came down with it and swiftly designed not only the light, semirigid framework used by most airships, but also the engines used to propel them and the hydrogen extractors that pulled the necessary gasses out of thin air. Alexander Pilkington discovered how to temper glass so it would keep an edge without shattering, allowing the creation of glass blades and electric lights that didn’t break.

Unfortunately, such geniuses became notoriously unstable as the disease continued to devour their brains. They went completely mad in the end; for all that they showed no other physical symptoms. Due to their penchant for complicated machinery, many people called them clockworkers. People also called them lunatics, bedbugs, fireflies, and any number of less-flattering names.

Alice grimaced. This particular clockworker seemed to have discovered how to control his plague-ridden brethren through hypnotic music. She had no idea where he’d come from or what he hoped to accomplish. At the moment, she didn’t care. All she wanted, with every fiber of her being, was to get away and find her way home without touching a zombie. The ones on the street might or might not be at the infectious stage, but Alice had no intention of finding out.

Her original cab was not a possibility—that zombie was still inside it. The cab horse snorted again and tossed its head but miraculously remained where it was. The blinders no doubt prevented it from understanding everything that was going on.

The grinning man continued to play the eerie music, and two zombies shambled around the cab, one from each side. They limped toward Alice, ragged clothes seeming to fade into the yellow fog, as if they wore the mist itself. Alice was surrounded—zombies to her left and right, a zombie in the cab ahead of her, and a brick wall behind. No doorways to dodge into, no stairs to climb. Nowhere to flee. Desperately, she cast about for a weapon or a distraction, anything. The zombies shuffled closer. One was a woman in a torn house-dress. Alice fumbled under her heavy skirts in an attempt to wrench off a shoe, but the buttons were done up too tightly. Tears streamed down her face.

“Get away!” she screamed at them. “Get away from me!”

A shot cracked through the fog. The head of the zombie woman exploded like a ripe melon. An awful smell washed over Alice as the body dropped to the sidewalk. Alice gaped. A horse rode up—two horses, no, four—their iron shoes clattering on the cobblestones. One of the riders rushed at Alice, stomping over the zombie woman’s corpse.

“Up you come,” the rider said, hauling Alice up behind the saddle in an awkward sideways perch. Alice, clutching for purchase and fighting The Dress, barely had time to register the fact that her rescuer was a woman in leather trousers before the horse wheeled around and cantered back the way it had come, leaving the two remaining zombies behind. Alice noted the pistol at the woman’s belt.

“Who are you?” Alice demanded. “What’s going on?”

“We’re here to help,” the woman said. “Down you go. Stay safe, love.”

Before Alice could register the shocking familiarity of the address, the woman deposited her on the street. The other horseback riders were shooting at the zombies and working their way toward the grinning clockworker. He continued to play, then abruptly turned, caught Alice’s eye, and winked. Alice took a backward step, uncertain. She was clear of the zombie mob now. She could run. But the tableaux tugged at her. Now that she was out of immediate danger, the scene turned more fascinating than frightening, and she wanted to stay. She could help somehow, should help. They had helped her. Still, she was half turning to flee when another thought whipped through her mind.

Louisa wouldn’t run.

With that, Alice turned back, and the clockworker threw her a wide grin as he played and played. The music scraped over Alice’s bones with the edge of a butcher’s knife. She was the only person left on the street besides the mysterious horsemen—and horsewomen. Another rider was pushing his way toward the sea of zombies, lashing out with a truncheon and using his horse to shoulder his way through the crowd toward the clockworker. But the clockworker seemed to glide away without effort, still surrounded by a zombie mob. Their screeches and groans half threatened to drown out the ever-present music. Yet another rider was forced to abandon his horse and leap atop the overturned beer truck. The horse disappeared, screaming, beneath a pile of ragged, half-dead plague victims.

“I could use a bit of help over here!” the rider shouted as three zombies clawed slowly up the side of the truck toward him. He kicked at one, a male in a tattered opera cloak, and the zombie lost its grip.

“On the way!” the woman rider shouted back from the edge of the zombie crowd. She drew her pistol and shot one of the other zombies crawling up the truck. Blood sprayed. The zombie fell backward, dead. Alice put a hand to her mouth.

A cart careened around the corner on two wheels, its horses in a lather. It skidded to a stop not far from Alice. A young man in a dark topcoat, work boots, and twill trousers dropped the reins and leapt to the back of the cart, where he whipped a canvas cover off an enormous... thing. It looked to Alice like a calliope that had lost a fight with a steam engine. Some of the pipes had come loose, and the young man was thrusting them back into place. Alice watched with fascination. The clockworker continued pouring out demonic music that drowned out the voice of God.

“Hurry with that, d’Arco!” the rider on the truck shouted, still kicking at zombies. The woman and the other riders circled the zombie mob, shooting where they could and trying to find a way to reach the clockworker.

D’Arco sat down at the machine, pumped at a few pedals, and slammed the ivory keyboard with both hands. A chord tooted from the pipes. The sound was jarring, almost dissonant. It was also barely audible over the clockworker’s music. Alice heard d’Arco say a word she wasn’t supposed to know. He pumped the pedals harder and tried again. The chord came out louder this time. Several of the zombies paused. So did the clockworker. He stared across the cobblestones at d’Arco. For a long moment, the two locked eyes. Then the clockworker changed his melody. With a blood-chilling sound of dozens of bare feet slapping stone in unison, every zombie on the street turned smartly to face d’Arco—and Alice.

“Uh-oh,” d’Arco said.

The clockworker snapped out notes in a quick tempo, and the zombies marched forward, straight for the cart. D’Arco nervously played his chord again, but he’d had little time to pump up the bellows attached to the pedals under his machine, and the sound came out differently. The clockworker laughed and continued to play. Alice backed away, then climbed into the wagon beside d’Arco, not sure what to do, but determined to do something. The other riders tried to slow the zombies like sheepdogs working a flock, but the zombies largely ignored them, even when they got trampled, and the three riders left on horses couldn’t hope to stop more than a hundred zombies on their own. What did the grinning man want?

“You’re doing it wrong!” Alice shouted at d’Arco. “It’s not affecting them!”

He ignored her, pumped furiously, and tried again. The ugly chords came out still louder this time, and the clockworker winced in the middle of his shambling army, though his playing continued. He added a new element to his tune, and one of the zombies picked up a chunk of wood from the overturned truck. It threw the piece straight at Alice. With a gasp, she ducked, and the piece of wood smashed into the machine. There was a pop, and hot steam hissed from the interior. The machine groaned and fell silent.

“Shit!” d’Arco said. The zombies were only a dozen paces away. His face pale beneath dark hair—he seemed to have lost his hat—he jumped down to the cobblestones and pulled an enormous rifle from a rack strapped to the side of the wagon. A cable ran from the stock of the rifle to another machine, the size of a Saint Bernard, bolted to the wagon floor.

“Pull that lever on the rear of the power pack!” d’Arco yelled.

Alice saw the lever he meant. It was pointing down. She yanked back her skirts and gave it a kick to shove it upright. Lights glowed and dials flickered across the pack’s surface. Alice smelled ozone and wondered what Louisa would think of all this.

“That weapon hasn’t been tested!” the female rider called out.

“No time like the present!” d’Arco yelled back. He aimed the rifle at the advancing row of zombies and pulled the trigger.

A hum rose from the power pack. It grew louder and more intense. A bolt of lightning cracked from the rifle barrel and struck one of the zombies full in the chest. The zombie, a boy who couldn’t have been more than twelve, sparked and danced in place, then collapsed. The others continued forward.

“All that to hurt one zombie?” Alice said. “A real rifle would do more!”

D’Arco said nothing, but fiddled feverishly with several dials on the rifle, aimed it, and fired again. This time the electric bolt went wide and encompassed most of the zombies in the forefront. They froze, paralyzed but upright, as electricity poured from the strange rifle. The clockworker continued to play while the zombies behind pushed at their immobilized brethren, trying to knock them over. The electric field, however, seemed to be shocking them as well and pushing them back. The clockworker changed his tune yet again, and the zombies shoved harder, even as they groaned in pain. Several dials on the power pack drooped, and Alice had the feeling the electricity wouldn’t last much longer. A bead of sweat ran around d’Arco’s temple.

“To hell with the directive!” he shouted. “Shoot the damned clockworker!”

“We’re trying!” the woman shouted. “We can’t get a clear shot with all these zombies in the way.”

Alice’s eye fell on the calliope. Quickly, she pulled the piece of wood out and tossed it aside. At first glance, the throw seemed to have staved in the side of the machine and broken a steam pipe, but when she looked closer, she could see that one of the fittings had simply popped loose, depriving the calliope of its high-powered steam. She knelt next to it and reached in, but heat from the pipes threatened to sear her hands through her thin evening gloves. Damp steam swirled around her, condensing on her face. A glance down at The Dress told her it was already torn, either from her unexpected ride on the horse or from the moment she had jumped into the wagon. Quickly, she used the tear as a starting point to rip a chunk of thick cloth loose so she could protect her hands. Reaching inside, she managed to push the fittings back together and slide the lock back into place.

D’Arco was still trying to hold the zombies back with the rifle, but already the electricity was weakening. The zombies were starting to move again, and they were nearly close enough to grab d’Arco. He was panting, either from fear or effort; Alice couldn’t tell which. She scrambled to the bench at the strange calliope and, thanking God for the music lessons Father had forced on her, pumped the pedals that worked the bellows.

“I have repaired your machine, Mr. d’Arco,” she called down to him. “What should I play?”

He glanced over his shoulder at her, utter surprise written across his face. Clearly, he’d forgotten all about her.

“I hardly suppose they want to hear ‘God Save the Queen,’ ” she prompted, still pumping. “But they are getting closer, sir, and that rifle of yours is nearly played out.”

The electricity sputtered and went out, then started up again, weaker than before. The zombies jerked forward. The grinning clockworker played his jaunty tune.

“A tritone,” d’Arco said. “Play a tritone!”

Alice put her fingers on the keys, still pumping. She could feel the pressure building in the machine. Tiny jets of steam spurted from the calliope’s seams. “Which one?”

“Any one! Just play!”

The rifle spat once more and went out. The zombies lurched forward, reaching for d’Arco. Alice set her fingers on the keys for C and F-sharp—an interval called a tritone because it consisted of exactly three whole steps—and pressed.

The machine roared.

Every zombie in the area clapped hands over its ears and howled. Several collapsed to the ground. The clockworker screamed. He dropped his instrument and the music stopped. Alice pumped the foot bellows and hit the chord again. The clockworker fell to the ground amid the zombies and vanished from her view. Alice played the awful chord again and again. It pounded the air like an angry train whistle. The calliope throbbed beneath her fingers, and her thighs grew tired from the pumping, but she kept going.

At last, she became aware of a hand on her shoulder. She looked up into the face of the female rider. You can stop, she mouthed.

Alice stopped. The calliope groaned to silence, and Alice sat on the bench, panting and sweaty despite the chilly night air.

“Are you all right?” the woman asked. She had a pleasant, round face, chocolate eyes, and light brown hair pulled into a French braid. The nails on her hand were bitten to the quick, and she still wore the leather trousers, though the puffy blouse with the lace at the throat was distinctly feminine.

“I’m... I’m fine,” Alice said. “What happened? Is everyone else all right?”

“Everyone’s fine, thanks to you, love,” the woman said. “You were a wonder! How did you understand Mr. d’Arco’s machine?”

“It was obvious,” Alice replied, “to anyone with a bit of sense. What happened to the zombies?”

“Some are still unconscious, and some have wandered away. Without the clockworker to guide them, they reverted to their normal behavior, poor things.” She gestured at the street behind her. It was empty but for the wreckage of the beer truck and the people on horseback. A single zombie slunk into the darkness, dragging one leg.

“Good heavens,” Alice said. She put a palm to her mouth as elation threatened to overtake her and swell her corsets. A sudden urge to jump up and down and clap her hands like a little girl swept over her, and she barely managed to contain herself. “We did it. We actually did it!”

The woman laughed. “Indeed we did.”

“What about the clockworker, then?” Alice asked.

“He got away.” The woman grimaced. “There was a sewer cover directly beneath him, and he dropped down into it right after you began to play. It was almost as if he’d planned it that way. Perhaps he did.”

Alice blew out a long breath, her elation somewhat deflated. “I’m sorry.”

“It wasn’t your fault, love,” the woman said. “You did far better than we did.”

There it was again—that familiar form of address. It should have bothered Alice, coming from a commoner, even from someone who was probably an Ad Hoc woman, but in the aftermath of the fight, she found it endearing instead, as if she’d been welcomed into a circle of tight-knit friends.

“But what did the clockworker want?” Alice demanded. “What was all that for?”

The woman shrugged. “Clockworkers live in a world of their own. No doubt gathering an army of zombies to tip over beer vans made perfect sense to him. Did they touch you?”

“No.” Alice glanced down at her ruined gown. “But I don’t think I’ll be wearing this again. And it was my only one.”

The woman clucked her tongue. “I’m sorry about that.”

“How does that machine work?” Alice asked, suddenly eager to change the subject. “And why did Mr. d’Arco need me to play a tritone?”

“Ah. I’m afraid I can’t go into that here,” the woman said. “But listen, love, there’s clearly quite a lot to you, far more than that dress can contain. If you ever need help, or if you find you need a change in your life, write to me, all right?”

She handed Alice a card. On it was written:

“Are you an Ad Hoc woman?” Alice blurted.

Glenda smiled. “Of course. There should be no other kind, if you ask me.”

At that moment, d’Arco rode up on Glenda’s horse, his dark eyes inquisitive beneath mussed black curls. Alice noted for the first time how handsome d’Arco was. His features were even, his jaw long, his smile wide. His body was long and lean beneath his topcoat.

“Did you thank her?” he asked. “Did you tell her she was wonderful?”

“I did, Simon,” Glenda said. “And I’ll thank you to give me Roulette back. You can drive the cart back to headquarters.”

“Your cab is still sitting over there,” d’Arco told Alice as he dismounted. “I’d offer to see you home, but we simply can’t leave the machinery. Can you drive it? What am I saying—a woman of your talents could probably shoe the horse.” And Alice had to laugh.

This, she decided, must be how Louisa felt all the time.

When she arrived home, she climbed down from the hansom cab and, not knowing what else to do, left it in the street. The horse would no doubt eventually return to its stable on its own, or its owner would remember Alice’s address and come looking for it, or someone would steal the beast. Alice had to admit she didn’t much care at this point. She retrieved her pocketbook from the cab floor and wearily climbed the short steps to the run-down row house she shared with her father, Arthur, Baron Michaels. When she entered, a clockwork cat leapt down from the windowsill with a light clicking of iron claws. It peered up at her, segmented tail switching back and forth, lamplit eyes glowing with unearthly green phosphor.

Alice reached down to pat the cat’s head. “Hello, Click. I’m glad you waited up for me.”

The cat made a rumbling noise that sounded nearly like a purr, batted at her tattered sleeves, then abruptly scrambled to his feet and rushed out of the room. Alice shook her head and suddenly realized she was starving. She tiptoed past her father’s study-cum-bedroom and slipped into the tiny kitchen, where she threw together a sandwich, her dress bulging inconveniently about her. Click jumped up on the counter to watch, his phosphorous eyes casting small circles of light over the bread and ham. He swatted at her hand, and she tapped his nose with the knife handle with a thin clank in admonishment.

“You don’t even eat,” she said.

Click meowed at her, somehow managing to sound a little huffy. He looked as if he wanted to say something, but actual speech wasn’t part of the codex that ran the tiny analytical engine in his head, and for this Alice was wryly grateful—a talking clockwork cat would be dreadfully obnoxious.

She put sandwich and tea on a tray with a candle and bustled upstairs, not wanting to awaken Father. The thought of having to explain the condition of The Dress to him filled her with dread.

The yellow fog continued to shoulder itself against the windows as Alice entered her room. Her candle provided only a little light, but putting on a gas jet would cost too much. Like Father’s study, Alice’s room lacked much furniture, but Alice had learned to weave rag rugs, and they added warmth to the floor. Under the window stood her workbench—a tall table with several drawers under it and a stool to sit on. Several wooden shipping boxes were stacked on the floor, all of them with Alice’s address on them. Cogs, flywheels, and tiny barrels for analytical engines littered the tabletop, and an array of tools hung neatly on hooks from the wall above. Standing incongruously nearby was a dressmaker’s stand for The Dress.

Alice flung open the wardrobe. “Out, please,” she said. “I need help.”

From the wardrobe flittered, crawled, and scampered a dozen small machines, automatons of brass and copper. Some skittered on half a dozen legs; others buzzed about beneath whirling blades. All of them possessed tiny, intelligent eyes and long-fingered hands.

“I need to get ready for bed,” Alice told them.

The automatons instantly set to work. They zipped about the room, their tiny hands tugging Alice out of The Dress, or what remained of it, clicking and squeaking to themselves all the while. Petticoats and lacings and corset all fell away, layer by layer. The automatons unfastened dozens and dozens of buttons. One of the automatons, a flier, seemed to be having trouble staying aloft. It labored, then dropped toward the floor. Alice caught it, halted the others in their work, and took the little machine to her workbench. Standing in her petticoats, she popped the key from the windup mechanism, deactivating the automaton, and swiftly disassembled it.

Alice hadn’t built her automatons, of course. They had arrived in pieces at Christmas, her birthday, Easter, even Guy Fawkes Night, along with complicated instructions for assembly and activation. And always at the bottom of every box of parts lay hidden a small pasteboard card with a handwritten scrawl: Love, Aunt Edwina.

The little automatons had started off fairly simple and had become more and more complicated over the years. Assembling them had given Alice quite an education in mechanics, engineering, and basic physics, and sometimes she wondered if that was the purpose Aunt Edwina had in mind.

Alice barely remembered her aunt Edwina. According to her father, the last time he had spoken to her was after Alice’s ninth birthday, just before the clockwork plague struck the Michaels family. It had killed Alice’s mother and older brother, forced her father into a wheelchair, and marked the Michaelses as socially undesirable. Aunt Edwina had withdrawn to her small estate outside London, snubbing the society that was trying to snub her and living her life as she liked. She wore trousers instead of skirts, talked to strange men without a proper introduction, and supported suffrage years before the Hats-Off Committee appeared in Parliament. In order to wheedle his way back into the social graces of the traditional folk, Arthur Michaels publicly repudiated his sister’s behavior and declared her a bad influence, though he didn’t refuse the little automatons she sent to Alice.

Click jumped up on the workbench, and Alice briefly touched the cat’s smooth head before going to back to work, her stiff petticoats hitched unbecomingly around her knees. Click had arrived fully assembled as an engagement present from Aunt Edwina three years ago, when Alice was eighteen. Father had arranged a marriage to Frederick Trent, a business associate. Knowing she had few other prospects, Alice hadn’t protested. In a stunningly unfortunate series of events, however, Frederick Trent himself contracted the clockwork plague from an errant beggar and died a week before the wedding.

What few social and business contacts had been left to Arthur Michaels quickly dried up. His investments went bad, and he’d been forced to sell the family home. Debts and bad business moves had decreased their fortunes further. Now they couldn’t even afford a girl to come in and sweep. And the daughter of a baron was socially forbidden from finding paying work, no matter how many useful skills she might have. Even Ad Hoc ladies would find the idea of a baron’s daughter laboring for mere money horrifying. More than once, Alice had considered disguising herself somehow and finding a job, but the only skill she had was assembling and repairing automatic machinery, and since most automatons were owned by nobility, she stood a good chance of being recognized. The possibility of being caught out made her too nervous to try it.

Alice donned a jeweler’s loupe to magnify the tiny machinery and saw one of the propeller gears was missing several teeth. Alice plucked a replacement from a drawer with a pair of tweezers, dropped it into place, and tightened the tiny bolt. She had already sold several of Aunt Edwina’s gift automatons without telling Father, and she wondered how long it would be before she ran out of machines to sell. Her greatest fear was that she might have to sell Click.

Deftly she finished reassembling the little automaton, unable to help but admire how its smooth brass surface hid a number of greasy, whirling bits of machinery. Her quick fingers rewound the brass key, and the automaton whirled to life. Its eyes snapped open, its blades spun it aloft, and it flew, chittering, across the room to join the others. They caressed it and squeaked among themselves.

“Enough of that now,” Alice told them with mock sternness. “I want my nightshirt.”

The automatons scampered and flew to obey. They removed the remainder of Alice’s petticoats and helped Alice pull the worn nightshirt over her head. The undergarments, at least, were undamaged. She kicked The Dress into the corner before wolfing down the sandwich. One of the automatons picked up a bit of pasteboard from the floor and handed it to Alice. It was Glenda Teasdale’s card, the one with the square root of two on it—a mystery indeed. And what on earth was the Third Ward?

Alice frowned as she finished the last bite of sandwich. Miss Teasdale was an Ad Hoc woman, wearing trousers, riding astride, calling a peer of the realm love as if they were related. Earlier, Alice had found it exciting, but now that she’d had time to calm down, she realized how ridiculous the entire affair was. And she had sacrificed an extremely expensive dress to this Third Ward for barely a thank-you. Glenda Teasdale and her Third Ward could go hang.

Alice Michaels tossed the card onto her workbench, blew out the candle, and dropped into exhausted, righteous sleep.