It was the size and shape of a human skull, but it seemed to be made entirely of crystal. The moonlight reflected through it, inside it. It had grinning crystal teeth, and its hollow eye sockets seemed to be staring directly at Cassie.

There was a frozen instant, and then Faye grabbed for it.

"Uh-uh," Adam said, holding it away from her. "No."

"Where did you get that?" said Faye. Her voice was no longer lazy, but full of barely contained excitement.

Even through her numbness Cassie felt a twinge of apprehension at her tone, and she saw the swift glance Adam exchanged with Diana. Then he turned to Faye. "On an island."

"Which island?"

"I didn't know you were so interested. You never seemed to be before."

Faye glared. "One way or another I'll find out, Adam."

"There's nothing else where I found it. Believe me, this was the only one of the Master Tools hidden there."

Faye took a breath and then relaxed and smiled. "Well, the least you can do is give us all a chance to look at it."

"No," said Diana. "Nobody even touches it yet. We don't know anything about this except that it was used by the old coven - by Black John himself. That means it's dangerous."

"Do we know for sure this is the crystal skull Black John wrote about?" Melanie asked, her voice quiet and rational.

"Yes," Adam said. "At least, it fits the description in the old records exactly. And I found it in a place just like the place Black John described. I think it's the real thing."

"Then it needs to be cleared and purified and studied before any of us work with it," Diana said. She turned to Cassie. "Black John was one of the leaders of the original coven," she said. "He died not long after New Salem was founded, but before that he took the coven's most powerful tools and hid them. For safekeeping, he said - but really because he wanted them for himself. For personal gain and revenge," she said, looking at Faye meaningfully. "He was an evil man, and anything he touched is going to be full of negative influences. We're not going to use it until we're sure it's safe."

If Black John had had anything to do with this skull, he must have been bad, Cassie thought. In some way she couldn't explain, she could feel darkness emanating from it. If she hadn't been so heartsick and dizzy, she would have said so - but surely everyone else could see for themselves.

"The old coven never found the lost Master Tools," Laurel was saying. "They searched, because Black John had left some clues about where he might have hidden them, but they didn't have any luck. They made new tools, but none were ever as powerful as the originals."

"And now we've found one," Adam said, with a flash of excitement in his blue-gray eyes.

Diana lightly touched the back of his hand as it held the skull. She smiled up at him, and the message between them was clearer than words: pride and triumph shared. This was their project, something they'd been working on for years, and now they had succeeded at last.

Cassie clenched her teeth against the pain in her breastbone. They deserve a chance to be alone and enjoy it, she thought. With brittle, forced cheerfulness she said, "You know, I'm getting tired. I think maybe it's time..."

"Of course," Diana said, instantly concerned. "You must be exhausted. We all are. We can talk more about this at the meeting tomorrow."

Cassie nodded, and nobody else made any objections. Not even Faye. But as Diana was instructing Melanie and Laurel to walk Cassie up the beach to her house, Cassie accidentally met Faye's gaze. There was an odd, calculating expression in those golden eyes that would have bothered her if she hadn't been beyond caring by now.

At home, every light was blazing, even though the first streaks of dawn hadn't yet appeared over the ocean. Melanie and Laurel walked Cassie inside, and they found her mother and grandmother both sitting up in the parlor - a stiff old-fashioned room at the front of the house. The two women were wearing nightgowns and robes. Cassie's mother's hair was loose down her back.

Cassie saw at once by their faces that they knew.

Is this what I was brought here for? she thought. To join the Circle? There was no longer any doubt in her mind that she'd been brought here, deliberately, and for a very specific reason.

She got no answer from the voices inside her, not even from the deepest voice. And that was disturbing.

But she didn't have time to worry about it. Not now. She looked at her mother's face, drawn and anxious, but also full of a kind of half-concealed pride and hope. Like a mother watching her daughter high-dive in the Olympics, and waiting for the judges' scores. Her grandmother looked the same.

Suddenly, despite the aching pain in her chest, Cassie was filled with a surge of protective love for them. Both of them. She managed a smile as she and Melanie and Laurel stood in the doorway.

"So, Grandma," she said, "does our family have a Book of Shadows?"

The tension broke into laughter as the two women rose.

"Not that I know of," her grandmother said. "But anytime you like, we'll take another look through the attic."

The meeting on Wednesday afternoon was tense. Everyone was on edge. And Faye clearly had a hidden agenda.

All she wanted to talk about was the skull. They should use it, she said, and immediately. All right, then, if not use it, at least check it out.

Try to activate it, see what imprints had been left on it.

Diana kept saying no. No checking it out. No activating it. They needed to purify it first. Ground it. Clear it. Which Faye knew would take weeks, if done properly. As long as Diana was in charge -

Faye said that at this rate Diana might not be in charge for long. In fact, if Diana kept refusing to test out the skull, Faye just might call for a leadership vote right now instead of waiting until November. Was that what Diana wanted?

Cassie didn't understand any of it. How do you check out a skull? Or ground it or clear it? But this time the argument was too heated for anyone to remember to explain to her.

She spent the entire meeting not watching Adam, who had tried to speak to her beforehand, but whom she'd managed to evade. She clung grimly to her resolve all the way through, even though the energy it took to ignore him exhausted her. She made herself not look at his hair, which had grown a little longer since she'd seen him, or at his mouth, which was as handsome and humorous as ever. She refused to let herself think about his body as she'd seen it on the beach in Cape Cod, with its flat, sinewy muscles and bare long legs. And most of all, she forced herself not to look into his eyes.

The one thing Cassie did glean from the meeting was that Diana was in a precarious position. "Temporary" leader meant that the coven could call a vote at any time and depose her, although the official vote was in November for some reason. And Faye was obviously looking for support so that she could take over.

She'd gotten the Henderson brothers on her side by saying they should use the skull right away to find Kori's killer. And she'd gotten Sean on her side simply by terrorizing him, it looked like. Deborah and Suzan, of course, had supported her from the beginning.

That was six. It would have been six on Diana's side too, but Nick refused to voice an opinion. He showed up at the meeting, but sat through it smoking and looking as if he were somewhere else. When asked, he said it didn't matter to him whether they used the skull or not.

"So you see, you're overruled," Faye told Diana, her honey-colored eyes hot with triumph. "Either you let us use the skull - or I call for a vote right now and we see if you still come out leader."

Diana's jaw was set. "All right," she said flatly, at last. "We'll try to activate it - just activate it and no more - on Saturday. Is that soon enough for you?"

Faye nodded graciously. She'd won, and she knew it.

"Saturday night," she said, and smiled.

Kori's funeral was on Friday. Cassie stood with the other members of the Club and cried along with them during the service. Afterward, at the cemetery, a fight broke out between Doug Henderson and Jimmy Clark, the boy Kori had gone with that summer. It took the entire Club to get them apart. The adults seemed scared to touch them.

Saturday dawned clear and cool. Cassie went over to Diana's in the evening after spending most of the day staring at a book, pretending to read it. She was worried about the skull ceremony, but she was even more worried about Adam. No matter what happens, she told herself, no matter what, I won't let anyone know how I feel. I'll keep it a secret forever if it kills me.

Diana looked tired, as if she hadn't been getting enough sleep. It was the first time the two of them had been alone together since the initiation - since Adam came. Sitting in Diana's pretty room, looking at the prism in the window, Cassie could almost pretend that Adam hadn't come, that he didn't exist. Things had been so simple then; she'd been happy just to be with Diana.

She noticed, for the first time, another wall of art prints like the ones she'd seen the first day.

"Are these goddesses too?" she asked.

"Yes. That's Persephone, daughter of the goddess of growing things." Diana's voice was soft with tiredness, but she smiled at the picture. It showed a slender girl laughing as she picked an armful of flowers. All around her it was springtime, and her face was filled with the joy of being young and alive.

"And who's that?"

"Athena. She was the goddess of wisdom. She never married either, like Artemis, the goddess of the hunt. All the other gods used to go to her for advice."

It was a tall goddess with a wide brow and clear, calm gray eyes. Well, of course they're gray; it's a black-and-white print, Cassie told herself. But somehow she felt they'd be gray anyway, and full of cool, thoughtful intelligence.

Cassie turned to the next print. "And who's - "

Just then there was the sound of voices downstairs. "Hello? Anybody up there? The front door was unlocked."

"Come on up," Diana called. "My dad's at work - as usual."

"Here," Laurel said, appearing in the doorway. "I thought you might like these. I got them along the way." She held out an armful of mixed flowers to Diana.

"Oh, Bouncing Bet! They're such a pretty pink, and I can dry them for soap later. And wild snapdragon and sweet melilot. I'll go get a vase."

"I would have brought some roses from the garden, but we used them all for purifying the skull."

Melanie smiled at Cassie. "So how's our newest witch?" she said, her cool gray eyes not unsympathetic. "Totally confused?"

"Well... a little confused. I mean" - Cassie picked at random one of the things she didn't understand - "how do you purify a skull with roses?"

"You'd better ask Laurel that; she's the expert on plants."

"And Melanie," said Laurel, "is the expert on stones and crystals, and this is a crystal skull."

"But just what is a crystal, exactly?" Cassie said. "I don't think I even know that."

"Well." Melanie sat down at Diana's desk as Diana came back and began to arrange the flowers. Laurel and Cassie sat on the bed. Cassie really did want to know about the things the Circle used to do magic. Even if she could never do the one spell she wanted to, she was still a witch.

"Well, some people call crystals 'fossilized water,' " Melanie said, her voice taking on a mock-lecturing tone. "Water combines with an element to make them grow. But I like to think of them as a beach."

Laurel snorted and Cassie blinked. "A beach?"

Melanie smiled. "Yes. A beach is sand and water, right? And sand is silicon. When you put silicon with water, under the right conditions, it forms silicon dioxide - quartz crystal. So water plus sand plus heat plus pressure equals a crystal. The remains of an ancient beach."

Cassie was fascinated. "And that's what the skull is made of?"

"Yes. It's clear quartz. There are other kinds of quartz too; other colors. Amethyst is purple. Laurel, are you wearing any?"

"What a question. Especially with a ceremony tonight." Laurel pushed her long, light-brown hair back to show Cassie her ears. In each she was wearing a dangling crystal of a deep violet color. "I like amethysts," she explained. "They're soothing and balancing. If you wear them along with rose quartz, it helps draw love to you."

Cassie's stomach clenched. As long as they could stay off subjects like love she'd be all right. "What other stones are there?" she asked Melanie.

"Oh, lots. In the quartz family there's citrine - Deborah wears a lot of that. It's yellow and it's good for physical activity. Energy. Fitness. That sort of thing."

"Deborah needs a little less energy," Laurel muttered.

"I like to wear jade," Melanie went on, twisting her left wrist to show Cassie a beautiful bracelet. It was set with a pale green, translucent oval stone. "Jade is peaceful, calming. And it sharpens mental clarity."

Cassie spoke hesitantly. "But... do these things really work? I mean, I know all the New Agers are into crystals, but - "

"Crystals are not New Age," Melanie said with a quelling glance at Laurel, who seemed about to argue the point. "Gemstones have been used since the beginning by ancient peoples - and sometimes even for the right things. The problem is that they're only as good as the person using them. They can store energy and help you call on the Powers, but only if you have the talent for it in the first place. So for most people they're pretty useless."

"But not for us," said Laurel. "Although they don't always work the way you'd expect. Things can get out of control. Remember when Suzan simply covered herself in carnelians and almost got mobbed at the football game? I thought there was going to be a riot."

Melanie laughed. "Carnelians are orange and very - stimulating," she said to Cassie. "You can get people overexcited if you use them wrong. Suzan was trying to attract the quarterback, but she nearly wound up with the entire team. I'll never forget her in the bathroom, pulling all those carnelians out of her clothes." Cassie burst into laughter at the picture.

"You're not supposed to wear orange or red stones all the time," Laurel added, grinning. "But of course Suzan won't listen. Neither will Faye."

"That's right," Cassie said, remembering. "Faye does wear a red stone on her necklace."

"It's a star ruby," Melanie said. "They're rare, and that one's very powerful. It can amplify passion - or anger - very quickly."

There was something else Cassie wanted to ask. Or rather, that she had to ask, whether she wanted to or not. "What about a stone like - chalcedony?" she said casually. "Is that good for anything?"

"Oh, yes. It has a protective influence - it can guard you against the harshness of the world. In fact, Diana, didn't you give... ?"

"Yes," said Diana, who had been sitting quietly on the window seat, listening. Now she smiled faintly in reminiscence. "I gave Adam a chalcedony rose when he left this summer. That's a special kind of chalcedony piece," she explained to Cassie. "It's flat and round and it has a sort of swirling spiral pattern in it, like a rose's petals. It has little quartz crystals sprinkled over it."

And tiny black shell things on the back, Cassie thought. She felt sick. Even the present he had given her was Diana's.

"Cassie?" They were all looking at her.

"Sorry," she said, opening her eyes and faking a smile. "I'm okay. I - I guess I'm a little wound up about this thing tonight. Whatever it is."

They were immediately sympathetic. Diana nodded grimly, showing more animation than she had since Cassie had arrived that evening. "I'm worried myself," she said. "It's way too soon. We shouldn't be doing this yet - but we don't have any choice."

Melanie said to Cassie, "You see, the skull absorbed energies from whoever used it last. Like an imprint of what was done, and who did it. We want to see what those are. So we'll all concentrate on it, and see what it will show us. Of course, we might not be able to activate it at all. Sometimes only a certain person can do that, or a certain code of sounds or lights or movements. But if we can, and if it's safe, we can eventually use its energy to show us things - like maybe who killed Kori."

"The larger the crystal, the more energy in it," Diana said bleakly. "And this is a big crystal."

"But why did the old coven carve it into a skull?" Cassie asked.

"They didn't," Melanie said. "We don't know who did, but it's much older than three hundred years. There are other crystal skulls out there in the world - nobody really knows how many. Most of them are in museums and things - there's one, the British Skull, that's in the Museum of Mankind in England. And the Templar Skull belongs to some secret society in France. Our old coven just got hold of this one somehow and used it."

"Black John used it," Diana corrected. "I wish Adam had found any of the other Master Tools instead of this one. This one was his, Black John's favorite, and I think he might have used it to get rid of people. I'm afraid that tonight - I don't know. But I'm afraid something awful is going to happen."

"We won't let it," said a new voice at the door. Cassie's heart began to pound dully and blood rushed to her face.

"Adam," said Diana. She relaxed visibly as he came over to the window seat to kiss her and sit beside her. She always seemed both more tranquil and more radiant whenever he was around.

"We'll keep the ceremony under strict control tonight," he said. "And if anything dangerous starts to happen, we'll just stop it cold. Did you get the garage ready?"

"No, I was waiting for you. We can take it down now." Diana unlocked the large cabinet, and Cassie saw the crystal skull resting in a Pyrex baking dish full of pink rose petals.

"Looks like John the Baptist's head," she murmured.

"I've used salt and rainwater to try and clear it," Diana said. "But what it really needs is a full course of crystals and flower essences, and then to be buried in moist sand for a few weeks."

"We'll take every precaution," Adam said. "A triple circle of protection. It'll be all right." He picked up the skull, with a few rose petals still clinging to it, and he and Diana left for the garage. Cassie watched him go.

"Don't be nervous," Melanie told her. "You won't really have to do anything at the ceremony. You won't be able to; it takes a long time to get the hang of scrying - years, usually. All you have to do is sit there and not break the Circle."

Cassie tried not to mind the condescending note in her voice. "Listen, do we have time for anybody to drive me over to my house?" she said. "There's something there I'd like to pick up."

Diana's garage was empty - of cars, at least. The floor was clean and bare, except for a circle drawn in white chalk.

"I'm sorry to make us all sit on concrete," Diana said, "but I wanted to do this inside - where I can be sure the wind won't blow out one of the candles."

There were a number of white candles lying at the center of the circle. They formed a smaller ring. In the very center of that, something draped with a piece of black cloth sat on a shoe box.

"All right," Diana said to the rest of the group, who had arrived in small clusters and were now standing in the garage. "Let's get this thing over with."

She had changed into her white shift and jewelry. Looking at them now, Cassie suspected that the diadem and cuff bracelet - and maybe even the garter - had some mystic significance. She watched Diana "cast" the circle, going around it with the dagger and then with water and then incense and then a lit candle. Earth, water, air, and fire. There were also some incantations, which Cassie tried to follow. But when they all filed into the circle and sat down knee to knee as Diana instructed, any interest in the actual ceremony flew right out of her mind.

She had ended up between Faye and Adam. She didn't know how it had happened. She had been in line to sit next to Sean, but somehow Faye had gotten in front of her. Maybe Faye didn't want to sit by Adam. Well, neither did Cassie, although for a very different reason.

Adam's knee was pressing against hers. That was how Diana had told them to sit. She could feel the warmth of it, the solidity. She could think of nothing else.

On her other side, Faye smelled of some heady, tropical perfume. It made her slightly dizzy.

Then all the lights went out.

Cassie didn't see how it was done; she was sure no one left the seated circle. But the overhead fluorescent panels had abruptly gone off.

It was pitch-black in the garage. The only light now was the flame of the single candle Diana held. Cassie could see her face illuminated by it, but nothing else.

"All right," Diana said quietly. "We're just going to be looking for the last imprints left. Nothing more than that; nobody goes in really deep until we know what we're dealing with. And I don't have to tell anybody that whatever happens, we don't break the circle." She didn't look at Cassie as she said it, but several of the others did, as if to imply that maybe she did have to say it.

Diana touched the candle flame to the candle Melanie held out to her. The flame doubled. Then Melanie leaned over to light Deborah's candle, and there were three flames.

The fire went around the circle until Laurel gave it to Adam. Cassie's hand was trembling as she held up her candle to receive the flame from him. She hoped everyone would assume it was just general nervousness.

At last all twelve candles were lit and stuck in their own wax to the concrete floor. Each shed a pool of radiance and cast huge dark shadows of the seated figures on the walls.

Diana reached into the ring of candles and pulled off the black cloth.

Cassie gasped.

The skull was facing her directly, its empty eye sockets staring at her. But that wasn't the most alarming thing. The skull was glowing. The candle flames around it played on it, and the crystal in turn reflected and refracted the light. It almost looked - alive.

Around the circle the others had straightened, tensed.

"Now," said Diana. "Find someplace inside the skull that interests you. Concentrate on it, look at the details. Then look for more details. Keep looking until you find yourself drawn into the crystal."

Someplace that interests you? Cassie thought blankly. But when she looked carefully at the glowing skull, she saw that the crystal wasn't completely clear. There were gossamer webs and what looked like wisps of smoke inside it. There were internal fractures that seemed to be acting as prisms to form miniature landscapes. The closer Cassie looked, the more detail she saw.

That looks like a spiral or tornado, she thought. And that - that looks almost like a door. And a face...

She jerked her eyes away, stomach lurching. Don't be silly; it's just imperfections in the crystal, she told herself.

She was almost afraid to look again. But no one else seemed disturbed. Their shadows loomed and flickered on the walls, but all eyes were turned toward the skull.

Look at it! Now, she commanded.

When she looked back at the skull, she couldn't find the misty face again. There, that proves it was just a trick of the light, she thought. But the skull had developed another disturbing quality. Things seemed to be moving inside it. It was almost as if the skull were made of water, contained inside a thin skin, and things were drifting slowly around.

Oh, stop it and pick one detail to focus on, she ordered herself. The doorway, look at that. It isn't moving.

She stared at the little prismatic fracture in the left eye socket, just where the pupil of a real eye would be. It looked like a half-open door with light spilling out.

Look at it. Notice the detail.

Dizziness from Faye's perfume swept over her. She was looking - just looking. She could see the door. The more carefully she looked, the larger it seemed. Or perhaps she was coming closer.

Yes, closer... closer. She was losing her sense of space. The skull was so large now; it seemed to have no boundaries, no shape. It was all around her. It had become the world. The door was right in front of her.

She was inside the skull.