PROLOGUE

London, April 1878.

The demon exploded in a shower of ichor and guts.

William Herondale jerked back the dagger he was holding, but it was too late. The viscous acid of the demon’s blood had already begun to eat away at the shining blade. He swore and tossed the weapon aside; it landed in a filthy puddle and commenced smoldering like a doused match. The demon itself, of course, had vanished—dispatched back to whatever hellish world it had come from, though not without leaving a mess behind.

“Jem!” Will called, turning around. “Where are you? Did you see that? Killed it with one blow! Not bad, eh?”

But there was no answer to Will’s shout; his hunting partner had been standing behind him in the damp and crooked street a few moments before, guarding his back, Will was positive, but now Will was alone in the shadows. He frowned in annoyance—it was much less fun showing off without Jem to show off to. He glanced behind him, to where the street narrowed into a passage that gave onto the black, heaving water of the Thames in the distance. Through the gap Will could see the dark outlines of docked ships, a forest of masts like a leafless orchard. No Jem there; perhaps he had gone back to Narrow Street in search of better illumination. With a shrug Will headed back the way he had come.

Narrow Street cut across Limehouse, between the docks beside the river and the cramped slums spreading west toward Whitechapel. It was as narrow as its name suggested, lined with warehouses and lopsided wooden buildings. At the moment it was deserted; even the drunks staggering home from the Grapes up the road had found somewhere to collapse for the night. Will liked Limehouse, liked the feeling of being on the edge of the world, where ships left each day for unimaginably far ports. That the area was a sailor’s haunt, and consequently full of gambling hells, opium dens, and brothels, didn’t hurt either. It was easy to lose yourself in a place like this. He didn’t even mind the smell of it—smoke and rope and tar, foreign spices mixed with the dirty river-water smell of the Thames.

Looking up and down the empty street, he scrubbed the sleeve of his coat across his face, trying to rub away the ichor that stung and burned his skin. The cloth came away stained green and black. There was a cut on the back of his hand too, a nasty one. He could use a healing rune. One of Charlotte’s, preferably. She was particularly good at drawing iratzes.

A shape detached itself from the shadows and moved toward Will. He started forward, then paused. It wasn’t Jem, but rather a mundane policeman wearing a bell-shaped helmet, a heavy overcoat, and a puzzled expression. He stared at Will, or rather through Will. However accustomed Will had become to glamour, it was always strange to be looked through as if he weren’t there. Will was seized with the sudden urge to grab the policeman’s truncheon and watch while the man flapped around, trying to figure out where it had gone; but Jem had scolded him the few times he’d done that before, and while Will never really could understand Jem’s objections to the whole enterprise, it wasn’t worth making him upset.

With a shrug and a blink, the policeman moved past Will, shaking his head and muttering something under his breath about swearing off the gin before he truly started seeing things. Will stepped aside to let the man pass, then raised his voice to a shout: “James Carstairs! Jem! Where are you, you disloyal bastard?”

This time a faint reply answered him. “Over here. Follow the witchlight.”

Will moved toward the sound of Jem’s voice. It seemed to be coming from a dark opening between two warehouses; a faint gleam was visible within the shadows, like the darting light of a will-o’-the-wisp. “Did you hear me before? That Shax demon thought it could get me with its bloody great pincers, but I cornered it in an alley—”

“Yes, I heard you.” The young man who appeared at the mouth of the alley was pale in the lamplight—paler even than he usually was, which was quite pale indeed. He was bareheaded, which drew the eye immediately to his hair. It was an odd bright silver color, like an untarnished shilling. His eyes were the same silver, and his fine-boned face was angular, the slight curve of his eyes the only clue to his heritage.

There were dark stains across his white shirtfront, and his hands were thickly smeared with red.

Will tensed. “You’re bleeding. What happened?”

Jem waved away Will’s concern. “It’s not my blood.” He turned his head back toward the alley behind him. “It’s hers.”

Will glanced past his friend, into the thicker shadows of the alley. In the far corner of it was a crumpled shape—only a shadow in the darkness, but when Will looked closely, he could make out the shape of a pale hand, and a wisp of fair hair.

“A dead woman?” Will asked. “A mundane?”

“A girl, really. Not more than fourteen.”

At that, Will cursed with great volume and expression. Jem waited patiently for him to be done.

“If we’d only happened along a little earlier,” Will said finally. “That bloody demon —”

“That’s the peculiar thing. I don’t think this is the demon’s work.” Jem frowned. “Shax demons are parasites, brood parasites. It would have wanted to drag its victim back to its lair to lay eggs in her skin while she was still alive. But this girl—she was stabbed, repeatedly. And I don’t think it was here, either. There simply isn’t enough blood in the alley. I think she was attacked elsewhere, and she dragged herself here to die of her injuries.”

“But the Shax demon—”

“I’m telling you, I don’t think it was the Shax. I think the Shax was pursuing her—hunting her down for something, or someone, else.”

“Shaxes have a keen sense of scent,” Will allowed. “I’ve heard of warlocks using them to follow the tracks of the missing. And it did seem to be moving with an odd sort of purpose.” He looked past Jem, at the pitiful smallness of the crumpled shape in the alley. “You didn’t find the weapon, did you?”

“Here.” Jem drew something from inside his jacket—a knife, wrapped in white cloth. “It’s a sort of misericord, or hunting dagger. Look how thin the blade is.”

Will took it. The blade was indeed thin, ending in a handle made of polished bone. The blade and hilt both were stained with dried blood. With a frown he wiped the flat of the knife across the rough fabric of his sleeve, scraping it clean until a symbol, burned into the blade, became visible. Two serpents, each biting the other’s tail, forming a perfect circle.

“Ouroboros,” Jem said, leaning in close to stare at the knife. “A double one. Now, what do you think that means?”

“The end of the world,” said Will, still looking at the dagger, a small smile playing about his mouth, “and the beginning.”

Jem frowned. “I understand the symbology, William. I meant, what do you think its presence on the dagger signifies?”

The wind off the river was ruffling Will’s hair; he brushed it out of his eyes with an impatient gesture and went back to studying the knife. “It’s an alchemical symbol, not a warlock or Downworlder one. That usually means humans—the foolish mundane sort who think trafficking in magic is the ticket for gaining wealth and fame.”

“The sort who usually end up a pile of bloody rags inside some pentagram.” Jem sounded grim.

“The sort who like to lurk about the Downworld parts of our fair city.” After wrapping the handkerchief around the blade carefully, Will slipped it into his jacket pocket. “D’you think Charlotte will let me handle the investigation?”

“Do you think you can be trusted in Downworld? The gambling hells, the dens of magical vice, the women of loose morals …”

Will smiled the way Lucifer might have smiled, moments before he fell from Heaven. “Would tomorrow be too early to start looking, do you think?”

Jem sighed. “Do what you like, William. You always do.”

Southampton, May.

Tessa could not remember a time when she had not loved the clockwork angel. It had belonged to her mother once, and her mother had been wearing it when she died. After that it had sat in her mother’s jewelry box, until her brother, Nathaniel, took it out one day to see if it was still in working order.

The angel was no bigger than Tessa’s pinky finger, a tiny statuette made of brass, with folded bronze wings no larger than a cricket’s. It had a delicate metal face with shut crescent eyelids, and hands crossed over a sword in front. A thin chain that looped beneath the wings allowed the angel to be worn around the neck like a locket.

Tessa knew the angel was made out of clockwork because if she lifted it to her ear she could hear the sound of its machinery, like the sound of a watch. Nate had exclaimed in surprise that it was still working after so many years, and he had looked in vain for a knob or a screw, or some other method by which the angel might be wound. But there had been nothing to find. With a shrug he’d given the angel to Tessa. From that moment she had never taken it off; even at night the angel lay against her chest as she slept, its constant ticktock, ticktock like the beating of a second heart.

She held it now, clutched between her fingers, as the Main nosed its way between other massive steamships to find a spot at the Southampton dock. Nate had insisted that she come to Southampton instead of Liverpool, where most transatlantic steamers arrived. He had claimed it was because Southampton was a much pleasanter place to arrive at, so Tessa couldn’t help being a little disappointed by this, her first sight of England. It was drearily gray. Rain drummed down onto the spires of a distant church, while black smoke rose from the chimneys of ships and stained the already dull-colored sky. A crowd of people in dark clothes, holding umbrellas, stood on the docks. Tessa strained to see if her brother was among them, but the mist and spray from the ship were too thick for her to make out any individual in great detail.

Tessa shivered. The wind off the sea was chilly. All of Nate’s letters had claimed that London was beautiful, the sun shining every day. Well, Tessa thought, hopefully the weather there was better than it was here, because she had no warm clothes with her, nothing more substantial than a woolen shawl that had belonged to Aunt Harriet, and a pair of thin gloves. She had sold most of her clothes to pay for her aunt’s funeral, secure in the knowledge that her brother would buy her more when she arrived in London to live with him.

A shout went up. The Main, its shining black-painted hull gleaming wet with rain, had anchored, and tugs were plowing their way through the heaving gray water, ready to carry baggage and passengers to the shore. Passengers streamed off the ship, clearly desperate to feel land under their feet. So different from their departure from New York. The sky had been blue then, and a brass band had been playing. Though, with no one there to wish her good-bye, it had not been a merry occasion.

Hunching her shoulders, Tessa joined the disembarking crowd. Drops of rain stung her unprotected head and neck like pinpricks from icy little needles, and her hands, inside their insubstantial gloves, were clammy and wet with rain. Reaching the quay, she looked around eagerly, searching for a sight of Nate. It had been nearly two weeks since she’d spoken to a soul, having kept almost entirely to herself on board the Main. It would be wonderful to have her brother to talk to again.