"Stepping out?" said Henry incredulously. "With Gideon Lightwood?"

Sophie kept her attention on Charlotte, who was gazing at her, round- eyed. "I know what Mortmain is holding over Mr. Lightwood too," she said.

"Gideon only just found out. His father doesn't know he knows."

"Well, dear God, girl, don't just stand there," said Henry, who looked as poleaxed as his wife. "Tel us."

"Demon pox," said Sophie. "Mr. Lightwood's got it, has had for years, and it'l kil him in a right couple of months if he doesn't get the cure. And Mortmain said he can get it for him."

The room exploded in a hubbub. Charlotte raced over to Sophie; Henry call ed after her; Will leaped from his chair and was dancing in a circle. Tessa stayed where she was, stunned, and Jem remained beside her. Meanwhile, Will appeared to be singing a song about how he had been right about demon pox all along.

"Demon pox, oh, demon pox,

Just how is it acquired?

One must go down to the bad part of town

Until one is very tired.

Demon pox, oh, demon pox

I had it all along-

No, not the pox, you foolish blocks,

I mean this very song-

For I was right, and you were wrong!"

"Will!" Charlotte shouted over the noise. "Have you LOST YOUR MIND? CEASE THAT INFERNAL RACKET! Jem-"

Jem, rising to his feet, clapped his hands over Will 's mouth. "Do you promise to be quiet?" he hissed into his friend's ear.

Will nodded, blue eyes blazing. Tessa was staring at him in amazement; they all were. She had seen Will many things-amused, bitter, condescending, angry, pitying-but never giddy before.

Jem let him go. "Al right, then."

Will slid to the floor, his back against the armchair, and threw his arms up.

"A demon pox on all your houses!" he announced, and yawned.

"Oh God, weeks of pox jokes," said Jem. "We're for it now."

"It can't be true," said Charlotte. "It's simply-demon pox?"

"How do we know Gideon did not lie to Sophie?" asked Jem, his tone mild. "I am sorry, Sophie. I hate to have to say it, but the Lightwoods are not trustworthy. . . ."

"I've seen Gideon's face when he looks at Sophie," said Will. "It was Tessa who told me first that Gideon fancied our Miss Col ins, and I thought back, and I realized it was true. And a man in love-a man in love Will tell anything.

Betray anyone." He was staring at Tessa as he spoke. She stared back; she could not help it. Her gaze felt pulled to him. The way he looked at her, with those blue eyes like pieces of sky, as if trying to communicate something to her silently. But what on earth . . . ?

She did owe him her life, she realized with a start. Perhaps he had been waiting for her to thank him. But there had been no time, no chance! She resolved to thank him at the first opportunity that presented itself. "Besides, Benedict was holding a demon woman on his lap at that party of his, kissing her," Will went on, glancing away. "She had snakes for eyes. Each man to his own, I suppose. Anyway, the only way you can contract demon pox is by having improper relations with a demon, so . . ."

"Nate told me Mr. Lightwood preferred demon women," said Tessa. "I don't suppose his wife ever knew about that."

"Wait." It was Jem, who had suddenly gone very still. "Wil -what are the symptoms of demon pox?"

"Quite nasty," said Will with relish. "It begins with a shield-shaped rash on one's back, and spreads over the body, creating cracks and fissures in the skin-"

Jem expel ed a gasp of breath. "I-I shall return," he said, "in just a moment. By the Angel-"

And he vanished out the door, leaving the others staring after him.

"You don't think he has demon pox, do you?" Henry inquired of no one in particular.

I hope not, since we just got engaged, Tessa had the urge to say-just to see the looks on their faces-but repressed it.

"Oh, shut up, Henry," said Will, and looked as if he were about to say something else, but the door banged open and Jem was back in the room, panting, and holding a piece of parchment. "I got this," he said, "from the Silent Brothers-when Tessa and I went to see Jessamine." He gave Tessa a slightly guilty look from under his fair hair, and she remembered him leaving Jessamine's cel and returning moments later, looking preoccupied.

"It is the report on Barbara Lightwood's death. After Charlotte told us that her father had never turned Silas Lightwood over to the Clave, I thought I would inquire of the Silent Brothers if there was another manner in which Mrs.

Lightwood had died. To see if Benedict had also lied that she had died of grief."

"And had he?" Tessa leaned forward, fascinated.

"Yes. In fact, she cut her own wrists. But there was more." He looked down at the paper in his hand. "A shield-shaped rash, indicative of the heraldic marks of astriola, upon the left shoulder." He held it out to Will, who took it and scanned it, his blue eyes widening.

"A striola," he said. "That is demon pox. You had evidence that demon pox existed and you didn't mention it to me! Et tu, Brute!" He rol ed up the paper and hit Jem over the head with it.

"Ouch!" Jem rubbed his head rueful y. "The words meant nothing to me! I assumed it a minor sort of ailment. It hardly seemed as if it were what kil ed her. She slit her wrists, but if Benedict wanted to protect his children from the fact that their mother had taken her own life-"

"By the Angel," said Charlotte softly. "No wonder she kil ed herself.

Because her husband gave her demon pox. A nd she knew it." She whirled on Sophie, who made a little gasping noise. "Does Gideon know of this?"

Sophie shook her head, saucer-eyed. "No."

"But wouldn't the Silent Brothers be obligated to tell someone if they discovered this?" Henry demanded. "It seems-well, dash it, irresponsible to say the least-"

"Of course they would tell someone. They would tell her husband. And no doubt they did, but what of it? Benedict probably already knew," said Will.

"There would have been no need to tell the children; the rash appears when one has first contracted the disease, so they were too old for her to have passed it on to them. The Silent Brothers doubtless told Benedict, and he said 'Horrors!' and promptly concealed the whole thing. One cannot prosecute the dead for improper relations with demons, so they burned her body, and that was that."

"So how is it that Benedict is still alive?" Tessa demanded. "Should the disease not have kil ed him by now?"

"Mortmain," said Sophie. "He's been giving him drugs to slow the progress of the disease all this time."

"Slow it, not stop it?" asked Will.

"No, he's still dying, and faster now," said Sophie. "That's why he's so desperate, and he'l do anything Mortmain wants."

"Demon pox!" Will whispered, and looked at Charlotte. Despite his clear excitement, there was a steady light flickering behind his blue eyes, a light of sharp intel igence, as if he were a chess player examining his next move for potential advantages or drawbacks. "We must contact Benedict immediately," said Will. "Charlotte must play on his vanity. He is too sure of getting the Institute. She must tell him that though the Consul's official decision is not scheduled until Sunday, she has realized that it is he who Will come out ahead, and she wishes to meet with him and make peace before it happens."

"Benedict is stubborn-," Charlotte began.

"Not as much as is he is proud," said Jem. "Benedict has always wanted control of the Institute, but he also wants to humiliate you, Charlotte. To prove that a woman cannot run an Institute. He believes that Sunday the Consul Will rule to take the Institute away from you, but that does not mean he Will be able to pass up a chance to see you grovel in private."

"To what end?" Henry demanded. "Sending Charlotte to confront Benedict accomplishes what, exactly?"

"Blackmail," said Will. His eyes were burning with excitement. "Mortmain may not be in our grasp, but Benedict is, and for now that may be enough."

"You think he Will walk away from trying to get the Institute? Won't that simply leave the business for one of his fol owers to take up?" Jem asked.

"We're not trying to get rid of him. We want him to throw his full support behind Charlotte. To withdraw his chal enge and to declare her fit to run the Institute. His fol owers Will be at a loss; the Consul Will be satisfied. We hold the Institute. And more than that, we can force Benedict to tell us what he knows of Mortmain-his location, his secrets, everything."

Tessa said dubiously, "But I am almost certain he is more afraid of Mortmain than he is of us, and he certainly needs what Mortmain provides.

Otherwise he Will die."

"Yes, he will. But what he did-having improper relations with a demon, then infecting his wife, causing her death-is the knowing murder of another Shadowhunter. It would not be considered only murder, either, but murder accomplished through demonic means. That would call down the worst of all punishments."

"What is worse than death?" asked Tessa, and immediately regretted saying it as she saw Jem's mouth tighten almost imperceptibly.

"The Silent Brothers Will remove that which makes him Nephilim. He Will become Forsaken," said Will. "His sons Will become mundane, their Marks stripped. The name of Lightwood Will be stricken from the rol s of Shadowhunters. It Will be the end of the Lightwood name among Nephilim.

There is no greater shame. It is a punishment even Benedict Will fear."

"And if he does not?" said Jem in a low voice.

"Then, we are no worse off, I suppose." It was Charlotte, whose expression had hardened as Will had spoken; Sophie was leaning against the mantel, a dejected figure, and Henry, his hand on his wife's shoulder, looked unusual y subdued. "We Will call on Benedict. There is no time to send a proper message ahead; it Will have to be something of a surprise. Now, where are the call ing cards?"

Will sat upright. "You've decided on my plan, then?"

"It's my plan now," said Charlotte firmly. "You may accompany me, Will, but you Will fol ow my lead, and there Will be no talk of demon pox until I say so."

"But-but . . ." Will sputtered.

"Oh, leave it," said Jem, kicking Will, not without affection, lightly on the ankle.

"She's annexed my plan!"

"Will," Tessa said firmly. "Do you care more about the plan being enacted or about getting credit for it?"

Will pointed a finger at her. "That," he said. "The second one."

Charlotte rol ed her eyes skyward. "Wil iam, this Will be either on my terms or not at all."

Will took a deep breath, and looked at Jem, who grinned at him; Will let the air out of his lungs with a defeated sigh and said, "Al right, then, Charlotte. Do you intend for all of us to go?"

"You and Tessa, certainly. We need you as witnesses regarding the party.

Jem, Henry, there is no need for you to go, and we require at least one of you to remain and guard the Institute."

"Darling . . ." Henry touched Charlotte's arm with a quizzical look on his face.

She looked up at him in surprise. "Yes?"

"You're sure you don't want me to come with you?"

Charlotte smiled at him, a smile that transformed her tired, pinched face.

"Quite sure, Henry; Jem isn't technical y an adult, and to leave him here alone -not that he isn't capable-wil only add fuel to Benedict's fire of complaints.

But thank you."

Tessa looked at Jem; he gave her a regretful smile and, hidden behind the spread of her skirts, pressed her hand with his. His touch sent a warm rush of reassurance through her, and she rose to her feet, amid Will rising to go, while Charlotte sought for a pen to scribble a note to Benedict on the back of a flossed call ing card, which Cyril would deliver while they waited in the carriage.

"I'd best fetch my hat and gloves," Tessa whispered to Jem, and made her way to the door. Will was just behind her, and a moment later, the drawing room door swinging shut behind them, they found themselves alone in the corridor. Tessa was about to hurry down the hal toward her room, when she heard Will 's footsteps behind her.

"Tessa!" he called, and she swung around. "Tessa, I need to speak with you."

"Now?" she said, surprised. "I gathered from Charlotte that she wanted us to hurry-"

"Damn hurrying," said Will, coming closer to her. "Damn Benedict Lightwood and the Institute and all this business. I want to talk to you." He grinned at her. There had always been a reckless energy to him, but this was different-the difference between the recklessness of despair and the abandonment of happiness. But what an odd time to be happy!

"Have you gone quite mad?" she asked him. "You say 'demon pox' the way someone else might say 'massive surprise inheritance.' Are you real y that pleased?"

"Vindicated, not happy, and anyway, this isn't about the demon pox. This is about you and me-"

The drawing room door opened, and Henry emerged, Charlotte just behind him. Knowing Jem would be next, Tessa stepped away from Will hastily, though nothing improper had transpired between them at all. Except in your thoughts, said a little voice in the back of her mind, which she ignored. "Will, not now," she said under her breath. "I believe I know what it is you want to say, and you're quite right to wish to say it, but this isn't the time or place, is it? Believe me, I am as eager for the talk as you, for it has been weighing heavily on my mind-"

"You are? It has?" Will looked dazed, as if she had hit him with a rock.

"Wel -yes," said Tessa, looking up to see Jem coming toward them. "But not now."

Will fol owed her gaze, swal owed, and nodded reluctantly. "Then, when?"

"Later, after we go to the Lightwoods'. Meet me in the drawing room."

"In the drawing room?"

She frowned at him. "Real y, Will," she said. "Are you going to repeat everything I say?"

Jem had reached them, and heard this last remark; he grinned. "Tessa, do let poor Will gather his wits about him; he's been out all night and looks as if he can barely remember his own name." He put his hand on his parabatai's arm. "Come along, Herondale. You seem as if you need an energy rune-or two or three."