Cassie's piece of amethyst was quite large. It was a pendant, hanging from the claws of a silver owl with outspread wings, and it felt cool against Cassie's chest under her blue and white sweater. She checked in Diana's mirror to make sure it didn't make a bump and then touched it nervously. Cassie had had three stones so far: the chalcedony rose Adam had given her, the quartz necklace Melanie had put around her neck at the Homecoming dance, and the piece of hematite she'd found at Number Thirteen. She hadn't kept any of them long. The chalcedony she'd had to give back to Adam, the quartz had been lost that same night at the burying .ground, and the hematite had been stolen. She just hoped nothing was going to happen to this amethyst.

Clouds had gathered in the night, and the sky was steely-gray as Diana drove them to school that morning. And school these days was about as bleak as the weather. Hall monitors, wearing badges and wintry expressions, stood in every corridor waiting for someone to break the rules. Which usually didn't take very long; there were so many rules that it was impossible not to break one or two just by being alive.

"We almost got sent up for wearing a noisemakin' device," Chris said as they were walking down the hall at lunchtime.

Cassie tensed. "What did you do?"

"Bribed him," Doug said with a wicked grin. "We gave him a Walkman."

"My Walkman," Chris said, aggrieved.

"I wonder what the penalty for bribing a hall monitor is?" Laurel mused as they reached the cafeteria.

Cassie opened her mouth, but the words froze on her lips. Through the glass windows of the cafeteria she could see something that wiped all thought from her mind.

"Oh God," said Laurel.

"I don't believe it," Diana whispered.

"I do," Adam said.

In the very center of the cafeteria was a wooden structure that Cassie recognized from her history books. It was made in two parts, which when closed held a person's wrists and neck securely in place, protruding through holes from the other side.

The stocks.

And they were occupied.

There was a guy inside them, a big husky guy Cassie recognized from her algebra class. He'd danced with her at Homecoming, and he'd been overly familiar with his hands. He liked to talk back to teachers, too. But she'd never seen him do anything deserving of this.

"He won't get away with it," Diana was saying, her green eyes blazing with intensity.

"Who, the principal?" Deborah asked. She and Suzan and Nick were standing by the cafeteria door, waiting for the others. "He already has. He was taking some parents on a guided tour a few minutes ago and they came through here ... he showed it to them, for God's sake. Said it was part of a 'tough love' program. Said other schools made troublemakers stand on tables so everybody could look at them, but that he thought the stocks were more humane because you could sit down. He almost made it sound reasonable. And they were just nodding and smiling - they ate it up."

Cassie felt queasy. She was thinking of the Witch Dungeon at Salem, where she and Chris and Doug had scuttled through narrow corridors lined with tiny dark cells. The stocks gave her the same sick feeling in her stomach. How can people do this to other people? she thought.

" - passing it off as part of our heritage," Nick was saying, his lip curled in disgust, and Cassie knew he felt the same way.

"Can we talk about it while we eat?" Suzan asked, shifting from one foot to the other. "I'm starving."

But as they made their way toward the back room - the private domain of the Club for the last four years - a short figure with rusty hair stepped in front of them.

"Sorry," Sally Waltman smirked. "That room is for hall monitors only, now."

"Oh, yeah?" said Deborah.

Two guys with badges appeared from nowhere and stood on either side of Sally.

"Yeah," one of them said.

Cassie looked through the glass windows of the back room - there was no crowd of hangers-on standing in front of it today - and saw Portia's tawny head. She was surrounded by girls and guys who were looking at her admiringly. They all wore badges.

"You'll just have to sit somewhere else," Sally was telling the Club. "And since there aren't enough seats at any one table, you'll have to break your group up. What a shame."

"We'll go outside," Nick said shortly, taking Cassie's arm.

Sally laughed. "I don't think so. No more eating out front. If you can't find a place to sit in here, you stand."

Cassie could feel Nick's muscles cord. She held on to his arm tightly. Diana had a similar hold on Adam, whose blue-gray eyes were like chips of steel, fixed on the guys beside Sally.

"It's not worth it," Diana said quietly, with forced calm. "It's what he wants. Let's go stand over there."

Sally looked disappointed as they all started to move to the wall. Then triumph flashed in her eyes.

"He's in violation already," she said, pointing to Doug. "He's wearing a radio."

"It's not on," Doug said.

"It doesn't have to be. Just wearing it is a Type-A offense. Come with me, please." The two guys surged forward to help Doug come.

"Nick, don't. Wait - " Cassie gasped, getting in front of him. A fight in the cafeteria was all they needed.

Doug's eyes were glittering wildly. He looked mad enough to hit Sally, not to mention the two guys.

"Bring him," Sally said in an exultant voice. The guys reached for Doug. Doug's fist jerked back. And then a throaty voice cut through the confusion.

"What's going on here?" Faye said, her amber eyes smoldering. She was wearing another of the little business suits; this one black and yellow.

Sally glared at her. "They're refusing to comply with the orders of a hall monitor," she said. "And he's wearing a radio."

Faye reached over and unhooked the Walkman from Doug's belt. "Now he's not," she said. "And I'm telling them to go eat somewhere else - outside, maybe. On my authority."

Sally was sputtering. Faye chuckled and led the Club out of the cafeteria.

"Thanks," Diana said, and for a moment she and Faye looked each other in the eye. Cassie thought of the candles burning in a circle on the road. A new stage of life - was Faye entering a new stage of life? Coming back to the coven?

But Faye's next words undeceived her. "You know, there's no reason that you can't eat in the back room," she said. "You can all become hall monitors. That's what he wants - "

"He wants to take us over," interrupted Deborah scornfully.

"He wants to join with us. He's one of us."

"No, he's not, Faye," Cassie said, thinking of the shadow under the rock. "He's nothing like us."

Faye gave her a strange glance, but all she said was, "There's a hall monitors' meeting in C-207 last period. Think about it. The sooner you join him, the easier things will be." She tossed Doug's Walkman back to him with a negligent gesture and walked away.

Lunch was uncomfortable; it was cold in the front yard of the school, and nobody but Suzan had much of an appetite. Sean showed up late, after all the excitement was over. They discussed plans to fight Black John, but as always they came back to the single issue of power. They needed power to fight him effectively. They needed the Master Tools.

Everyone had a different idea of where to search. Adam proposed the beach - especially around Devil's Cove, where Mr. Fogle, the former principal, had been killed by a rock slide. Deborah thought maybe the old burying ground. "It's been here since the 1600s," she said. "The original coven could easily have hidden things there." Melanie and Diana discussed the possibility of making a crystal pendulum designed to seek out traces of "white energy" the tools might be giving off.

Cassie sat quietly, close to Nick, not saying much. She had the stupid, desperate urge to forget all of this and bury her head in his shoulder. She didn't know New Salem as well as the others - how could she come up with a reasonable place to search? And she had such a feeling of dread, of evil things just waiting to happen.

We're going to lose, she thought, listening to the worried voices of the others. We're just kids, and he's got centuries of experience. We're going to lose.

The feeling of dread got worse as the day went on. She ran into Nick as she was walking to her last class and he stopped in the hall.

"You look awful," he said.

"Thanks." Cassie tried a wry smile for him.

"No, I mean you're so pale - you feeling okay? Do you want to go home?"

"Leaving school grounds without permission," Cassie quoted automatically, tiredly, and then she was in his arms.

Nick said, "They can take their permission and - "

Cassie just clung to him. Nick was so good to her; she wanted to love him. She would make herself love him, she decided. Maybe they should go back to Crowhaven Road; go someplace where they could be alone. Nick didn't like doing this kind of thing where people could see.

"Hold me," she said. He did. Then he kissed her.

Yes. Just go with it. Be part of Nick - that was safe. Nick would take care of her. She could stop thinking now.

"Well, well, well . . . looks like a Type-A violation to me," an officious voice said. "Public displays of affection, inappropriate to the serious and dignified purpose of formal education. What do you say, Portia?"

Nick and Cassie broke apart, Cassie flushing.

"I think it's just too revolting," Portia Bainbridge said.

Behind her was a gaggle of hall monitors, on their way to the meeting, apparently. There were maybe thirty of them. Cassie's heart was suddenly beating hard and fast.

"And it's her fault," Portia went on, looking down her aristocratic nose at Cassie. "I heard her initiate it. Let's take her in."

"That's right, the little flirt," Sally said. Cassie remembered Sally's voice in the bathroom; the anger in it, the viciousness. This one had every guy at Homecoming dance following her around with his tongue hanging out - including my boyfriend. She'd come to think of herself so differently since she'd overheard Sally talking about her that day.

Nick was looking at the group of monitors, his face cold - like the old Nick, the one Cassie had first met. Cold as ice. "Take her where? The penalty for a Type-A offense is supposed to be detention. Or don't you read your own rules?" he said.

"We decide what the penalties are - " Portia began, but Sally interrupted.

"She was refusing to cooperate with a hall monitor at lunchtime," she said. "That's what we're taking her in for. Mr. Brunswick gave us special instructions. "We're going to take her to the office - she can talk to him."

"Then you can take both of us," Nick said. His arm tightened on Cassie.

There were too many of them. Cassie's eyes skimmed over the crowd of hall monitors, seeing not a friendly face among them. All seniors, all kids who hated witches. And Faye wasn't here now.

"Nick," she said, her voice soft and careful over the thumping of her heart, "I think I'd better go with them." She glanced back at Sally. "Can I just say good-bye to him?"

Looking sardonic, Sally nodded. Cassie put her arms around Nick's neck.

"Get the others," she whispered in his ear. "The monitors will be in their meeting - you'll have to find a way to get me out."

As he drew back, Nick's mahogany eyes met hers in acknowledgement. Then, with an expressionless look at Sally, he stood aside.

The group of monitors surrounded Cassie and escorted her down the hall, treating her like a mass murderer. She had a wild impulse to giggle, but as they reached the office the urge disappeared in a flood of sheer dread and anxiety.

He planned this, she thought. Maybe not this specifically, today. But he knew he'd get us somehow, one by one. She tried to ignore the little voice whispering, he knew he'd get you. It's you he's after.

Because she was an outsider - or because she didn't fit in with his plans. A vision of Kori flashed through her mind: Kori lying stiff and motionless with a broken neck at the bottom of the hill. She'd seen what happened to people who didn't fit in with Black John's plans.

"Maybe if you bat your eyes at him he'll let you off," Sally whispered spitefully and pushed her in the office door.

Cassie didn't answer. She couldn't.

She hadn't been in this office since she'd gone to Mr. Fogle to complain that Faye was persecuting her. It looked the same, except that there was a crackling fire in the fireplace now. And the man behind the desk was different.

Don't look at him, Cassie thought, as the door swung shut behind her, but she couldn't help it. Those black eyes held hers from the instant she glanced toward the desk. That hawklike face betrayed no sign of surprise that she was there.

The principal put a slim gold-plated pen on the desk with a barely audible click.

"Cassandra," he said.

Cassie's knees felt weak.

It was the voice of the shadow. A dark, liquid voice. So quiet, so insidious - so evil. Under his hematite-black eyes she felt naked, exposed. As if he were looking at her mind. Looking for a crack to get in.

"Mr. Brunswick," she said. Her voice sounded strange to her own ears. Polite, but distant.

He smiled.

He was wearing a black turtleneck and a black jacket. He stood, resting his fingertips on the desk.

"So brave," he said. "I'm proud of you."

It was the last thing she expected. Cassie just stared at him. Her fingers flew automatically to the bump of the amethyst pendant under her sweater.

His eyes followed the movement. "I wouldn't bother," he said, smiling faintly. "That crystal is much too small to be effective."

Cassie's hand dropped slowly. How had he known? She felt so confused, so off-balance. She stared at the man in front of her, trying to connect him with the burned creature that had crouched over her grandmother in the kitchen, with the seventeenth-century wizard who had led a frightened coven to New Salem. How was he here at all, that was the question. What was the source of his power?

"And amethyst is a weak stone, a stone of the heart," he was going on softly. "Purity of purpose, Cassie; that's the secret. Purity and clarity. Never forget your purpose."

She had the strange feeling he was answering her question. Oh God, why didn't Nick come? Her heart was pounding so hard . . . she was frightened.

"Let me demonstrate," the dark man said. "If you would give me that pendant? For a moment only," he added, as Cassie stood motionless.

Slowly, Cassie reached around the back of her neck. With cold fingertips she undid the silver chain and removed it. She didn't know what else to do.

Slowly, precisely, he took it.

Suddenly, wildly, Cassie thought of a magician about to do a trick. Nothing up those sleeves, she thought. Only flesh that shouldn't be there in the first place.

Still holding the necklace in the air, the principal turned away from Cassie. The fire leaped and crackled and Cassie felt her pulse in her throat and fingertips. I can't stand much more of this, she thought. Nick, where are you?

"You see," the principal said, in a voice that seemed oddly distorted, "amethyst is a stone riddled with impurities. For power, quartz is always my choice . . ." He began to turn around.

No, thought Cassie. Everything had gone into slow motion, as if she were watching one frame after another of a video. A video played on a very superior machine, each frame crisp and bright and sharp-edged, with no blurriness. Cassie didn't even know where the No had come from, except that something deep in her own brain was screaming in protest, trying to warn her. Don't look, oh, don't look.

Cassie wanted to stop the action, to freeze the frame. But she couldn't. It was taking forever, but the dark man was still turning. He was facing her.

She saw the elegant black jacket, the black turtleneck sweater. But above the turtleneck was a monstrosity that forced tears from her eyes and clogged the scream in her throat. The man had no face.

No hair, no eyebrows, no eyes, no nose. No mouth, only a grinning outline of clenched teeth. Even that, even the stark bones which faced her, were as clear as water.

Cassie couldn't scream, couldn't breathe. Her mind was out of control.

Oh God, oh God the skull isn't gone no wonder we couldn't find it, it didn't explode at all because it's in his head, oh Diana oh Adam it's in his head ...

"You see, Cassandra," came the inhuman voice from behind those clenched teeth, "purity plus clarity equals power. And I have more power than you children have ever dreamed of."

Oh God I won't believe this I won't believe this is happening I don't want to see any more ...

"My spirit is not confined to this body," the voice went on calmly, with terrible lucidity. "It can flow like water wherever I direct it. I can focus its power anywhere."

The hollow eyesockets tilted down, toward the amethyst pendant which hung from a perfectly normal-looking hand. Firelight flickered deep inside the crystal. Then Cassie felt it - an outrush of power like the one she'd sent to scare the dog and to warn Sean and to light the match. Only this was much stronger, much more concentrated than her feeble bursts had been. She could almost see it, like a blaze of light.

The amethyst pendant shattered.

The silver owl swung, but nothing hung from its claws now. The crystal was gone.

Cassie's ears caught the tinkle as bits of it fell. But she didn't really notice the sound consciously. She was blind and deaf with panic.

"Now, Cassandra," the voice was beginning again, and then it was interrupted by a noise so loud that even Cassie couldn't ignore it. A roar was coming from the front yard of the school, a sound like a pep rally, only angry. Shrill screams rang out against the background of deep shouting.

The principal dropped the silver chain and strode over to the window which overlooked the front of the school.

And Cassie's brain woke up. It wanted only one thing, to get out of here. With the dark man's attention distracted, she dove for the door.

She ran straight through the office without looking at the secretaries. There was chaos in the second-floor halls. Everyone was flooding out "of classrooms. "It's a fight!" some guy on the stairs was yelling. "Come on!"

It's like a riot; they can't control everybody at once, Cassie realized dimly. She was still running. She ran down the stairs and then down a hallway, instinctively heading for the center of the confusion.

"Cassie, wait!"

Not a man's voice, but a threatening one. Faye. Cassie paused for an instant, looking around desperately for Nick or Diana or Adam.

"Cassie, stop, for pity's sake. No one is trying to hurt you. I've been running after you all the way from the office."

Warily, Cassie edged backward. The hall was deserted now. Everyone was outdoors.

"Cassie, just listen to me. He's not trying to murder you, I promise. He wants to help you. He likes you."

"Faye, you're insane!" Cassie's control broke, and she screamed the words. "You don't know what he is! Everything you see about him is an illusion. He's a monster!"

"Don't be ridiculous. He's one of us - "

"Oh, my God, oh, my God," Cassie said. Reaction was setting in and her knees were shaking so badly that she had to lean against the wall. She slid down, tearing a poster about the Thanksgiving football game. "You didn't see him. You don't know."

"I know you're being a baby. You didn't even stay to listen to what he had to say to you. He was going to explain everything - "

"Faye, wake up!" Cassie cried. "For God's sake, will you please wake up and look at him?

He's nothing that you think. You're completely blind."

"You think you know so much about it." Faye stood back, arms crossed over her chest. She tilted her chin up and looked down at Cassie with heavy-lidded, queerly triumphant eyes. Her blood-red lips curved in a smile. "You think you know everything - but you don't even know what his name was when he was here last. When he came to our parents and he lived at Number Thirteen."

The strength of terror Cassie had felt moments earlier was gone, and the ground suddenly felt very unstable. She pressed a hand against the floor. Faye was still looking at her with those strange, triumphant eyes. "No," Cassie whispered.

"'No' you don't know? Or 'no' don't tell you? But I want to tell you, Cassie, and it's time you did know. The name he used last time was John Blake."