“And you’ve never asked him why?”

“If he wanted me to know, he’d tell me,” Jem said. “You asked why I think he tolerates me better than other people. I’d imagine it’s precisely because I’ve never asked him why.” He smiled at her, wryly. The cold air had whipped color into his cheeks, and his eyes were bright. Their hands were close to each other’s on the parapet. For a brief, half-confused moment Tessa thought that he might be about to put his hand over hers, but his gaze slid past her and he frowned. “Bit late for a walk, isn’t it?”

Following his gaze, she saw the shadowy figures of a man and a woman coming toward them across the bridge. The man wore a workman’s felt hat and a dark woolen coat; the woman had her hand on his arm, her face inclined toward his. “They probably think the same thing about us,” Tessa said. She looked up into Jem’s eyes. “And you, did you come to the Institute because you had nowhere else to go? Why didn’t you stay in Shanghai?”

“My parents ran the Institute there,” said Jem, “but they were murdered by a demon. He—it—was called Yanluo.” His voice was very calm. “After they died, everyone thought that the safest thing for me would be to leave the country, in case the demon or its cohorts came after me as well.”

“But why here, why England?”

“My father was British. I spoke English. It seemed reasonable.” Jem’s tone was as calm as ever, but Tessa sensed there was something he wasn’t telling her. “I thought I would feel more at home here than I would in Idris, where neither of my parents had ever been.”

Across the bridge from them the strolling couple had paused at a parapet; the man seemed to be pointing out features of the railway bridge, the woman nodding as he spoke. “And did you—feel more at home, that is?”

“Not precisely,” Jem said. “Almost the first thing I realized when I came here was that my father never thought of himself as British, not the way an Englishman would. Real Englishmen are British first, and gentlemen second. Whatever else it is they might be—a doctor, a magistrate or landowner—comes third. For Shadowhunters it’s different. We are Nephilim, first and foremost, and only after that do we make a nod to whatever country we might have been born and bred in. And as for third, there is no third. We are only ever Shadowhunters. When other Nephilim look at me, they see only a Shadowhunter. Not like mundanes, who look at me and see a boy who is not entirely foreign but not quite like them either.”

“Half one thing and half another,” Tessa said. “Like me. But you know you’re human.”

Jem’s expression softened. “As are you. In all the ways that matter.”

Tessa felt the backs of her eyes sting. She glanced up and saw that the moon had passed behind a cloud, giving it a pearlescent luster. “I suppose we should go back. The others must be worried.”

Jem moved to offer her his arm—and paused. The strolling couple Jem had noted before were suddenly in front of them, blocking their way. Though they must have moved very swiftly to reach the far side of the bridge so fast, they stood eerily still now, their arms linked. The woman’s face was concealed in the shadow of a plain bonnet, the man’s hidden beneath the brim of his felt hat.

Jem’s hand tightened on Tessa’s arm, but his voice was neutral when he spoke. “Good evening. Is there something we can help you with?”

Neither of them spoke, but they moved a step closer, the woman’s skirt rustling in the wind. Tessa looked around, but there was no one else on the bridge, no one visible at either embankment. London seemed utterly deserted under the blurring moon.

“Pardon me,” Jem said. “I’d appreciate it if you’d let me and my companion go by.” He took a step forward, and Tessa followed. They were close enough now to the silent couple that when the moon came out from behind its cloud, flooding the bridge with silvery light and illuminating the face of the man in the felt hat, Tessa recognized him instantly.

The tangled hair; the wide once-broken nose and scarred chin; and most of all the protruding, popping eyes, the same eyes as the woman who stood beside him, her blank stare fixed on Tessa in a manner terribly reminiscent of Miranda’s.

But you’re dead. Will killed you. I saw your body. Tessa whispered, “It’s him, the coachman. He belongs to the Dark Sisters.”

The coachman chuckled. “I belong,” he said, “to the Magister. While the Dark Sisters served him, I served them. Now I serve him alone.”

The coachman’s voice sounded different from how Tessa remembered—less thick, more articulate, with an almost sinister smoothness. Beside Tessa, Jem had gone very still. “Who are you?” he demanded. “Why are you following us?”

“The Magister has directed us to follow you,” the coachman said. “You are Nephilim. You are responsible for the destruction of his home, the destruction of his people, the Children of the Night. We are here to deliver a declaration of war. And we are here for the girl.” He turned his eyes to Tessa. “She is the property of the Magister, and he will have her.”

“The Magister,” said Jem, his eyes very silver in the moonlight. “Do you mean de Quincey?”

“The name you give him does not matter. He is the Magister. He has told us to deliver a message. That message is war.”

Jem’s hand tightened on the head of his cane. “You serve de Quincey but are not vampires. What are you?”

The woman standing beside the coachman made a strange sighing noise, like the high whistle of a train. “Beware, Nephilim. As you slay others, so shall you be slain. Your angel cannot protect you against that which neither God nor the Devil has made.”

Tessa began to turn toward Jem, but he was already in motion. His hand swung up, the jade-headed cane in it. There was a flash. A wickedly sharp and shimmering blade shot from the end of the cane. With a swift turn of his body, Jem plunged the blade forward and slashed it into the coachman’s chest. The man staggered back, a high whirring sound of surprise issuing from his throat.

Tessa drew in her breath. A long slash across the coachman’s shirt gaped open, and beneath it was visible neither flesh nor blood but shining metal, raggedly scored by Jem’s blade.

Jem drew his blade back, letting out a breath, satisfaction mixed with relief. “I knew it—”

The coachman snarled. His hand darted into his coat and withdrew a long serrated knife, the kind butchers used to cut through bone, while the woman, snapping into action, moved toward Tessa, her ungloved hands outstretched. Their movements were jerky, uneven—but very, very fast, much faster than Tessa would have guessed they could move. The coachman’s companion advanced on Tessa, her face expressionless, her mouth half-open. Something metallic gleamed inside it—metal, or copper. She has no gullet, and I would guess, no stomach. Her mouth ends in a sheet of metal behind her teeth.

Tessa retreated until her back hit the parapet. She looked for Jem, but the coachman was advancing on him again. Jem slashed away at him with the blade, but it seemed only to slow the man down. The coachman’s coat and shirt hung away from his body now in ragged strips, clearly showing the metal carapace beneath.

The woman grabbed for Tessa, who darted aside. The woman lumbered forward and crashed into the parapet. She seemed to feel no more pain than the coachman did; she drew herself stiffly upright and turned to move toward Tessa again. The impact seemed to have damaged her left arm, though, for it hung bent at her side. She swung toward Tessa with her right arm, fingers grasping, and seized her by the wrist. Her grip was tight enough to make Tessa scream as the small bones in her wrist flared with pain. She clawed at the hand that held her, her fingers sinking deep into slick, soft skin. It peeled away like the skin of a fruit, Tessa’s nails scraping against the metal beneath with a harshness that sent shivers up her spine.

She tried to jerk her hand back, but she only succeeded in pulling the woman toward her; she was making a whirring, clicking noise in her throat that sounded unpleasantly insectile, and up close her eyes were pupil-less and black. Tessa pulled her foot back to kick out—

And there was the sudden clang of metal on metal; Jem’s blade flashed down with a clean slice, cutting the woman’s arm in half at the elbow. Tessa, released, fell back, the bodiless hand falling from her wrist, striking the ground at her feet; the woman was jerking around toward Jem, whir-click, whir-click. He moved forward, striking at the woman hard with the flat of the cane, knocking her back a step, and then another and another until she hit the railing of the bridge so hard that she overbalanced. Without a cry she fell, plunging toward the water below; Tessa raced to the railing just in time to see her slip beneath the surface. No bubbles rose to show where she had vanished.

Tessa spun back around. Jem was clutching his cane, breathing hard. Blood ran down the side of his face from a cut, but he seemed otherwise unharmed. He held his weapon loosely in one hand as he gazed at a dark humped shape on the ground at his feet, a shape that moved and jerked, flashes of metal showing between the ribbons of its torn clothing. When Tessa moved closer she saw that it was the body of the coachman, writhing and jerking. His head had been sliced cleanly away, and a dark oily substance pumped from the stump of his neck, staining the ground.

Jem reached up to push his sweat-dampened hair back, smearing the blood across his cheek. His hand shook. Hesitantly Tessa touched his arm. “Are you all right?”

His smile was faint. “I should be asking you that.” He shuddered slightly. “Those mechanical things, they unnerve me. They—” He broke off, staring past her.

At the south end of the bridge, moving toward them with sharp staccato motions, were at least a half dozen more of the clockwork creatures. Despite the jerkiness of their movements, they were approaching swiftly, almost hurtling forward. They were already a third of the way across the bridge.

With a sharp click the blade vanished back into Jem’s cane. He seized Tessa’s hand, his voice breathless. “Run.”

They ran, Tessa clutching his hand, glancing behind only once, in terror. The creatures had made it to the center of the bridge and were moving toward them, gathering speed. They were male, Tessa saw, dressed in the same kind of dark woolen coats and felt hats as the coachman had been. Their faces gleamed in the moonlight.

Jem and Tessa reached the steps at the end of the bridge, and Jem kept a tight grip on Tessa’s hand as they hurtled down the stairs. Her boots slipped on the damp stone, and he caught her, his cane clattering awkwardly against her back; she felt his chest rise and fall against hers, hard, as if he were gasping. But he couldn’t be out of breath, could he? He was a Shadowhunter. The Codex said they could run for miles. Jem pulled away, and she saw that his face was tight, as if he were in pain. She wanted to ask him if he’d been hurt, but there was no time. They could hear clattering footsteps on the stairs above them. Without a word Jem took hold of her wrist again and pulled her after him.

They passed the Embankment, lit by the glow of its dolphin lamps, before Jem turned aside and plunged between two buildings into a narrow alley. The alley sloped up, away from the river. The air between the buildings was dank and close, the cobblestones slick with filth. Washing flapped like ghosts from windows overhead. Tessa’s feet were screaming in their fashionable boots, her heart slamming against her chest, but there was no slowing down. She could hear the creatures behind them, hear the whir-click of their movements, closer and closer.