"I suppose you're storing up all that charm now?" Tessa inquired. "Wouldn't want to waste any of it on us?"

"That's it exactly." Will sounded pleased. "And it isn't Charlotte the Starkweathers can't stand, Jem. It's her father."

"Sins of the fathers," said Jem. "They're not inclined to like any Fairchild, or anyone associated with one. Charlotte wouldn't even let Henry come up-"

"That is because every time one lets Henry out of the house on his own, one risks an international incident," said Will. "But yes, to answer your unasked question, I do understand the trust Charlotte has placed in us, and I do intend to behave myself. I don't want to see that squinty-eyed Benedict Lightwood and his hideous sons in charge of the Institute any more than anyone else does."

"They're not hideous," said Tessa.

Will blinked at her. "What?"

"Gideon and Gabriel," said Tessa. "They're really quite good-looking, not hideous at all."

"I spoke," said Will in sepulchral tones, "of the pitch-black inner depths of their souls."

Tessa snorted. "And what color do you suppose the inner depths of your soul are, Will Herondale?"

"Mauve," said Will.

Tessa looked over at Jem for help, but he only smiled. "Perhaps we should discuss strategy," he said. "Starkweather hates Charlotte but knows that she sent us. So how to worm our way into his good graces?"

"Tessa can utilize her feminine wiles," said Will. "Charlotte said he enjoys a pretty face."

"How did Charlotte explain my presence?" Tessa inquired, realizing belatedly that she should have asked this earlier.

"She didn't real y; she just gave our names. She was quite curt," said Will.

"I think it fal s to us to concoct a plausible story."

"We can't say I'm a Shadowhunter; he'l know immediately that I'm not. No Marks."

"And no warlock mark. He'l think she's a mundane," said Jem. "She could Change, but . . ."

Will eyed her speculatively. Though Tessa knew it meant nothing-worse than nothing, real y-she still felt his gaze on her like the brush of a finger across the back of her neck, making her shiver. She forced herself to return his look stonily. "Perhaps we could say she's a mad maiden aunt who insists on chaperoning us everywhere."

"My aunt or yours?" Jem inquired.

"Yes, she doesn't really look like either of us, does she? Perhaps she's a girl who's fal en madly in love with me and persists in following me wherever I go."

"My talent is shape-shifting, Will, not acting," said Tessa, and at that, Jem laughed out loud. Will glared at him.

"She had the better of you there, Will," he said. "It does happen sometimes, doesn't it? Perhaps I should introduce Tessa as my fiancee. We can tell mad old Aloysius that her Ascension is underway."

"Ascension?" Tessa remembered nothing of the term from the Codex.

Jem said, "When a Shadowhunter wishes to marry a mundane-"

"But I thought that was forbidden?" Tessa asked, as the train slid into a tunnel. It was dark suddenly in their compartment, though she had the feeling nevertheless that Will was looking at her, that shivering sense that his gaze was on her somehow.

"It is. Unless the Mortal Cup is used to turn that mundane into a Shadowhunter. It is not a common result, but it does happen. If the Shadowhunter in question applies to the Clave for an Ascension for their partner, the Clave is required to consider it for at least three months.

Meanwhile, the mundane embarks on a course of study to learn about Shadowhunter culture-"

Jem's voice was drowned out by the train whistle as the locomotive emerged from the tunnel. Tessa looked at Will, but he was staring fixedly out the window, not looking at her at all. She must have imagined it.

"It's not a bad idea, I suppose," said Tessa. "I do know rather a lot; I've finished nearly all of the Codex."

"It would seem reasonable that I brought you with me," said Jem. "As a possible Ascender, you might want to learn about Institutes other than the one in London." He turned to Will. "What do you think?"

"It seems as fine an idea as any." Will was still looking out the window; the countryside had grown less green, more stark. There were no vil ages visible, only long swathes of gray-green grass and outcroppings of black rock.

"How many Institutes are there, other than the one in London?" Tessa asked.

Jem ticked them off on his hands. "In Britain? London, York, one in Cornwal -near Tintagel-one in Cardiff, and one in Edinburgh. They're all smal er, though, and report to the London Institute, which in turn reports to Idris."

"Gideon Lightwood said he was at the Institute in Madrid. What on earth was he doing there?"

"Faffing about, most likely," said Will.

"Once we finish our training, at eighteen," said Jem, as if Will hadn't spoken, "we're encouraged to travel, to spend time at other Institutes, to experience something of Shadowhunter culture in new places. There are always different techniques, local tricks to be learned. Gideon was away for only a few months. If Benedict called him back so soon, he must think that his acquisition of the Institute is assured." Jem looked troubled.

"But he's wrong," Tessa said firmly, and when the troubled look didn't leave Jem's gray eyes, she cast about for something to change the subject.

"Where is the Institute in New York?"

"We haven't memorized all their addresses, Tessa." There was something in Will 's voice, a dangerous undercurrent. Jem looked at him narrowly, and said: "Is everything all right?"

Will took his hat off and laid it on the seat next to him. He looked at them both steadily for a moment, his gaze level. He was beautiful to look at as always, Tessa thought, but there seemed something gray about him, almost faded. For someone who so often seemed to burn very brightly, that light in him seemed exhausted now, as if he had been rol ing a rock up a hil like Sisyphus. "Too much to drink last night," he said final y.

Really, why do you bother, Will? Don't you realize we both know you're lying? Tessa almost said, but one look at Jem stopped her. His gaze as he regarded Will was worried-very worried indeed, though Tessa knew he did not believe Will about the drinking, any more than she did. But, "Well," was all he said, lightly, "if only there were a Rune of Sobriety."

"Yes." Will looked back at him, and the strain in his expression relaxed slightly. "If we might return to discussing your plan, James. It's a good one, save one thing." He leaned forward. "If she is meant to be affianced to you, Tessa Will need a ring."

"I had thought of that," said Jem, startling Tessa, who had imagined he had come up with this Ascendant idea on the spot. He slipped his hand into his waistcoat pocket and drew out a silver ring, which he held out to Tessa on his palm. It was not unlike the silver ring Will often wore, though where Will 's had a design of birds in flight, this one had a careful etching of the crenel ations of a castle tower around it. "The Carstairs family ring," he said.

"If you would . . ."

She took it from him and slipped it onto her left ring finger, where it seemed to magical y fit itself. She felt as if she ought to say something like It's lovely, or Thank you, but of course this wasn't a proposal, or even a gift.

It was simply an acting prop. "Charlotte doesn't wear a wedding ring," she said. "I hadn't realized Shadowhunters did."

"We don't," said Will. "It is customary to give a girl your family ring when you become engaged, but the actual wedding ceremony involves exchanging runes instead of rings. One on the arm, and one over the heart."

"'Set me as a seal upon thine heart, as a seal upon thine arm: for love is strong as death; jealousy is cruel as the grave,'" said Jem. "Song of Solomon."

"'Jealousy is cruel as the grave'?" Tessa raised her eyebrows. "That's not . . . very romantic."

"'The coals thereof are coals of fire, which hath a most vehement flame,'"

said Will, quirking his eyebrows up. "I always thought females found the idea of jealousy romantic. Men, fighting over you . . ."

"Well, there aren't any graves in mundane wedding ceremonies," said Tessa. "Though your ability to quote the Bible is impressive. Better than my aunt Harriet's."

"Did you hear that, James? She just compared us to her aunt Harriet."

Jem, as always, was unruffled. "We must be on familiar terms with all religious texts," he said. "To us they are instruction manuals."

"So you memorize them all in school?" She realized she had seen neither Will nor Jem at their studies since she had been at the Institute. "Or rather, when you are tutored?"

"Yes, though Charlotte's rather fal en off in tutoring us lately, as you might imagine," said Will. "One either has a tutor or one is schooled in Idris-that is, until you attain your majority at eighteen. Which Will be soon, thankful y, for the both of us."

"Which one of you is older?"

"Jem," said Will, and "I am," said Jem, at the same time. They laughed in unison as well, and Will added, "Only by three months, though."

"I knew you'd feel compel ed to point that out," said Jem with a grin.

Tessa looked from one of them to the other. There could not be two boys who looked more different, or who had more different dispositions. And yet.

"Is that what it means to be parabatai?" she said. "Finishing each other's sentences and the like? Because there isn't much on it in the Codex."

Will and Jem looked at each other. Will shrugged first, casual y. "It is rather difficult to explain," he said loftily. "If you haven't experienced it-"

"I meant," Tessa said, "you cannot-I don't know-read each other's minds, or the like?"

Jem made a spluttering noise. Will 's lambent blue eyes widened. "Read each other's minds? Horrors, no."

"Then, what's the point? You swear to guard each other, I understand that, but aren't all Shadowhunters meant to do that for each other?"

"It's more than that," said Jem, who had stopped spluttering and spoke somberly. "The idea of parabatai comes from an old tale, the story of Jonathan and David. 'And it came to pass . . . that the soul of Jonathan was knit with the soul of David, and Jonathan loved him as his own soul. . . . Then Jonathan and David made a covenant, because he loved him as his own soul.' They were two warriors, and their souls were knit together by Heaven, and out of that Jonathan Shadowhunter took the idea of parabatai, and encoded the ceremony into the Law."

"But it doesn't just have to be two men. It can be a man and a woman, or two women?"

"Of course." Jem nodded. "You have only eighteen years to find and choose a parabatai. Once you are older than that, the ritual is no longer open to you. And it is not merely a matter of promising to guard each other. You must stand before the Council and swear to lay down your life for your parabatai. To go where they go, to be buried where they are buried. If there were an arrow speeding toward Will, I would be bound by oath to step in front of it."

"Handy, that," said Will.

"And he, of course, is bound to do the same for me," said Jem. "Whatever he may say to the contrary, Will does not break oaths, or the Law." He looked hard at Will, who smiled faintly and stared out the window.

"Goodness," said Tessa. "That's all very touching, but I don't see exactly how it confers any advantages."

"Not everyone has a parabatai," said Jem. "Very few of us, actual y, find one in the all otted time. But those who do can draw on the strength of their parabatai in battle. A rune put on you by your parabatai is always more potent than one you put on yourself, or one put on by another. And there are some runes we can utilize that no other Shadowhunter can, because they draw on our doubled power."

"But what if you decide that you don't want to be parabatai anymore?"

Tessa asked curiously. "Can the ritual be broken?"

"Dear God, woman," said Will. "Are there any questions you don't want to know the answer to?"

"I don't see the harm in tell ing her." Jem's hands were folded atop his cane. "The more she knows, the better she Will be able to pretend she plans to Ascend." He turned to Tessa. "The ritual cannot be broken save in a few situations. If one of us were to become a Downworlder or a mundane, then the binding is cut. And of course, if one of us were to die, the other would be free. But not to choose another parabatai. A single Shadowhunter cannot take part in the ritual more than once."

"It is like being married, isn't it," said Tessa placidly, "in the Catholic church. Like Henry the Eighth; he had to create a new religion just so he could escape from his vows."

"Til death do us part," said Will, his gaze still fixed on the countryside speeding past outside the window.

"Well, Will won't need to create a new religion just to be rid of me," said Jem. "He'l be free soon enough."

Will looked over sharply, but it was Tessa who spoke. "Don't say that," she admonished Jem. "A cure could still be found. I don't see any reason to abandon all hope."

She almost shrank back at the look Will bent on her: blue, blazing, and furious. Jem seemed not to notice as he replied, calmly and unaffectedly. "I haven't abandoned hope," he said. "I just hope for different things than you do, Tessa Gray."

Hours went by after that, hours during which Tessa nodded off, her head propped against her hand, the dull sound of the train's wheels winding its way into her dreams. She woke at last with Jem shaking her gently by the shoulders, the train whistle blowing, and the guard shouting out the name of York station. In a flurry of bags and hats and porters they descended to the platform. It was nowhere near as crowded as Kings Cross, and covered by a far more impressive arched glass and iron roof, through which could be glimpsed the gray-black sky.