The yel ow fog had thickened, and she could make out little through it-the dark shapes of people hurrying to and fro, the hazy words of advertising signs painted on the sides of buildings. Every once in a while the fog would part and she would get a clear glimpse of something-a little girl carrying bunches of wilting lavender, leaning against a wall, exhausted; a knife grinder rol ing his cart wearily homeward; a sign for Bryant and May's Lucifer Matches looming suddenly out of the gloom.

"Chuckaways," said Jem. He was leaning back against the seat across from her, his eyes bright in the dimness. She wondered if he had taken some of the drug before they left, and if so, how much.

"Pardon?"

He mimed the act of striking a match, blowing it out, and tossing the remainder over his shoulder. "That's what they call matches here- chuckaways, because you toss them aside after one use. It's also what they call the girls who work at the match factories."

Tessa thought of Sophie, who could easily have become one of those "chuckaways," if Charlotte hadn't found her. "That's cruel."

"It's a cruel part of the city we're going into. The East End. The slums." He sat forward. "I want you to be careful, and to stay close by me."

"Do you know what Will 's doing there?" Tessa asked, half-afraid of the answer. They were passing by the great bulk of St. Paul's now, looming up above them like a giant's glimmering marble tombstone.

Jem shook his head. "I don't. I only got a sense-a fleeting image of the street-from the tracking spell. I Will say, though, that there are few harmless reasons for a gentleman to go 'down to Chapel' after dark."

"He could be gambling . . ."

"He could be," Jem agreed, sounding as if he doubted it.

"You said you would sense it. Here." Tessa touched herself over the heart.

"If something had happened to him. Is that because you're parabatai?"

"Yes."

"So there's more to being parabatai than just swearing to look out for each other. There's something-mystical about it."

Jem smiled at her, that smile that was like a light suddenly being turned on in every room of a house. "We're Nephilim. Every one of our life's passages has some mystical component-our births, our deaths, our marriages, everything has a ceremony. There is one as well if you wish to become someone's parabatai. First you must ask them, of course. It's no smal commitment-"

"You asked Will," Tessa guessed.

Jem shook his head, still smiling. "He asked me," he said. "Or rather he told me. We were training, up in the training room, with longswords. He asked me and I said no, he deserved someone who was going to live, who could look out for him all his life. He bet me he could get the sword away from me, and if he succeeded, I'd have to agree to be his blood brother."

"And he got it away from you?"

"In nine seconds flat." Jem laughed. "Pinned me to the wall. He must have been training without my knowing about it, because I'd never have agreed if I'd thought he was that good with a longsword. Throwing daggers have always been his weapons." He shrugged. "We were thirteen. They did the ceremony when we were fourteen. Now it's been three years and I can't imagine not having a parabatai."

"Why didn't you want to do it?" Tessa asked a little hesitantly. "When he first asked you."

Jem ran a hand through his silvery hair. "The ceremony binds you," he said. "It makes you stronger. You have each other's strength to draw on. It makes you more aware of where the other one is, so you can work seamlessly together in a fight. There are runes you can use if you are part of a pair of parabatai that you can't use otherwise. But . . . you can choose only one parabatai in your life. You can't have a second, even if the first one dies. I didn't think I was a very good bet, considering."

"That seems a harsh rule."

Jem said something then, in a language she didn't understand. It sounded like "khalepa ta kala."

She frowned at him. "That isn't Latin?"

"Greek," he said. "It has two meanings. It means that that which is worth having-the good, fine, honorable, and noble things-are difficult to attain."

He leaned forward, closer to her. She could smel the sweet scent of the drug on him, and the tang of his skin underneath. "It means something else as well."

Tessa swal owed. "What's that?"

"It means 'beauty is harsh.'"

She glanced down at his hands. Slim, fine, capable hands, with blunt-cut nails, and scars across the knuckles. Were any of the Nephilim unscarred? "These words, they have a special appeal to you, don't they?" she asked softly. "These dead languages. Why is that?"

He was leaning close enough to her that she felt his warm breath on her cheek when he exhaled. "I cannot be sure," he said, "though I think it has something to do with the clarity of them. Greek, Latin, Sanskrit, they contain pure truths, before we cluttered our languages with so many useless words."

"But what of your language?" she said softly. "The one you grew up speaking?"

His lips twitched. "I grew up speaking English and Mandarin Chinese," he said. "My father spoke English, and Chinese badly. After we moved to Shanghai, it was even worse. The dialect there is barely intel igible by someone who speaks Mandarin."

"Say something in Mandarin," said Tessa with a smile.

Jem said something rapidly, that sounded like a lot of breathy vowels and consonants run together, his voice rising and fal ing melodical y: "Ni hen piao liang."

"What did you say?"

"I said your hair is coming undone. Here," he said, and reached out and tucked an escaping curl back behind her ear. Tessa felt the blood spil hot up into her cheeks, and was glad for the dimness of the carriage. "You have to be careful with it," he said, taking his hand back slowly, his fingers lingering against her cheek. "You don't want to give the enemy anything to grab hold of."

"Oh-yes-of course." Tessa looked quickly toward the window-and stared. The yel ow fog hung heavy over the streets, but she could see well enough. They were in a narrow thoroughfare-though broad, perhaps, by London's standards. The air seemed thick and greasy with coal dust and fog, and the streets were lined with people. Filthy, dressed in rags, they slumped against the wal s of tipsy-looking buildings, their eyes watching the carriage go by like hungry dogs following the progress of a bone. Tessa saw a woman wrapped in a shawl, a basket of flowers drooping from one hand, a baby folded into a corner of the shawl propped against her shoulder. Its eyes were closed, its skin as pale as curd; it looked sick, or dead. Barefoot children, as dirty as homeless cats, played together in the streets; women sat leaning against one another on the stoops of buildings, obviously drunk. The men were worst of all, slumped against the sides of houses, dressed in dirty, patched topcoats and hats, the looks of hopelessness on their faces like etchings on gravestones.

"Rich Londoners from Mayfair and Chelsea like to take midnight tours of districts like these," said Jem, his voice uncharacteristical y bitter. "They call it slumming."

"Do they stop and-and help in some way?"

"Most of them, no. They just want to stare so they can go home and talk at their next tea party about how they saw real 'mug-hunters' or 'dol ymops' or 'Shivering Jemmys.' Most of them never get out of their carriages or omnibuses."

"What's a Shivering Jemmy?"

Jem looked at her with flat silver eyes. "A freezing, ragged beggar," he said. "Someone likely to die of the cold."

Tessa thought of the thick paper pasted over the cracks in the windowpanes in her New York apartment. But at least she had had a bedroom, a place to lie down, and Aunt Harriet to make her hot soup or tea over the smal range. She had been lucky.

The carriage came to a stop at an unprepossessing corner. Across the street the lights of an open public house spilled out onto the street, along with a steady stream of drunkards, some with women leaning on their arms, the women's brightly colored dresses stained and dirty and their cheeks highly rouged. Somewhere someone was singing "Cruel Lizzie Vickers."

Jem took her hand. "I can't glamour you against the glances of mundanes,"

he said. "So keep your head down and keep close to me."

Tessa smiled crookedly but didn't take her hand out of his. "You said that already."

He leaned close and whispered into her ear. His breath sent a shiver racing through her whole body. "It's very important."

He reached past her for the door and swung it open. He leaped down onto the pavement and helped her down after him, pul ing her close against his side. Tessa looked up and down the street. There were some incurious stares from the crowds, but the two of them were largely ignored. They headed toward a narrow door painted red. There were steps around it, but unlike all the other steps in the area, they were bare. No one was sitting on them. Jem took them quickly, pul ing her up after him, and rapped sharply on the door.

It was opened after a moment by a woman in a long red dress, fitted so tightly to her body that Tessa's eyes widened. She had black hair piled on her head, kept in place by a pair of gold chopsticks. Her skin was very pale, her eyes rimmed with kohl-but on closer examination Tessa realized she was white, not foreign. Her mouth was a sulky red bow. It turned down at the corners as her gaze came to rest on Jem.

"No," she said. "No Nephilim."

She moved to shut the door, but Jem had raised his cane; the blade shot out from the base of it, holding the door open wide. "No trouble," he said.

"We're not here for the Clave. It's personal."

She narrowed her eyes.

"We're looking for someone," he said. "A friend. Take us to him, and we won't bother you further."

At that, she threw her head back and laughed. "I know who you're looking for," she said. "There's only one of your kind here." She turned away from the door with a shrug of contempt. Jem's blade slid back into its casing with a hiss, and he ducked under the low lintel, drawing Tessa after him.

Beyond the door was a narrow corridor. A heavy sweet smel hung on the air, like the smel that hung about Jem's clothing after he had taken his drug.

Her hand tightened involuntarily on his. "This is where Will comes to buy the -to buy what I need," he whispered, inclining his head so that his lips nearly touched her ear. "Although why he would be here now . . ."

The woman who had opened the door for them glanced back over her shoulder as she set off down the hall. There was a slit up the back of her dress, showing much of her legs-and the end of a long, slender forked tail, marked with black and white markings like the scales of a snake. She's a warlock, Tessa thought with a dull thud at her heart. Ragnor, the Dark Sisters, this woman-why was it that warlocks always seemed so-sinister? With the exception of Magnus perhaps, but she had the feeling Magnus was an exception to many rules.

The corridor widened out into a large room, its wal s painted dark red.

Great lamps, their sides carved and painted with delicate traceries that threw patterned light against the wal s, hung down from the ceiling. Along the wal s were ranged beds, in bunks, like the inside of a ship. A large round table dominated the center of the room. At it sat a number of men, their skin the same blood-red as the wal s, their black hair clipped close to their heads.

Their hands ended in blue-black talons that had also been clipped, probably to all ow them to more easily count and sift and mix the various powders and concoctions they had spread out before them. The powders seemed to glimmer and shine under the lamplight, like pulverized jewels.

"Is this an opium den?" Tessa whispered into Jem's ear.

His eyes were raking the room anxiously. She could sense the tension in him, a thrum just under the skin, like the fast-beating heart of a hummingbird.

"No." He sounded distracted. "Not real y-mostly demon drugs and faerie powders. Those men at the table, they're ifrits. Warlocks without powers."

The woman in the red dress was leaning over the shoulder of one of the ifrits. Together they looked up and over at Tessa and Jem, their eyes lingering on Jem. Tessa didn't like the way they were looking at him. The warlock woman was smiling; the ifrit's look was calculating. The woman straightened up and swayed over to them, her h*ps moving like a metronome under the tight satin of her dress.

"Madran says we have what you want, silver boy," said the warlock woman, raking a blood-red nail across Jem's cheek. "No need for pretense."

Jem flinched back from her touch. Tessa had never seen him look so unnerved. "I told you, we're here for a friend," he snapped. "A Nephilim. Blue eyes, black hair-" His voice rose. "Ta xian zai zai na li?"

She looked at him for a moment, then shook her head. "You are foolish,"

she said. "There is little of the yin fen left, and when it is gone, you Will die.

We struggle to obtain more, but lately the demand-"

"Spare us your attempts to sel your merchandise," said Tessa, suddenly angry. She couldn't bear the look on Jem's face, as if each word were the cut of a knife. No wonder Will bought his poisons for him. "Where is our friend?"

The warlock woman hissed, shrugged, and pointed toward one of the bunk beds bolted to the wall. "There."

Jem whitened as Tessa stared. Their occupants were so still that at first she had thought the beds were empty, but she realized now, looking more closely, that each was taken up by a sprawled figure. Some lay on their sides, arms trailing over the edges of the bed, hands splayed; most were on their backs, eyes open, staring at the ceiling or the bunk above them.

Without another word Jem began to stalk across the room, Tessa on his heels. As they drew closer to the beds, she realized that not all the occupants were human. Blue, violet, red, and green skin flashed past; green hair as long and netted as a web of seaweed brushed restlessly against a dirty pil ow; taloned fingers gripped the wooden sides of a bunk as someone moaned. Someone else was giggling softly, hopelessly, a sound sadder than weeping; another voice repeated a children's rhyme over and over and over again:

"Oranges and lemons

Say the bells of St. Clement's

When will ye pay me?

Ring the bells at Old Bailey

When I grow rich

Say the bells of Shoreditch-"

"Will," whispered Jem. He had stopped at a bunk halfway down the wall, and leaned against it, as if his legs threatened to give way.