The next morning was gray and much more typical of early autumn. Al I wanted to do was cocoon myself in layers of sweaters and stay in my rooms.

One glance at the heavy weather convinced me not to return to the river. I set out for a run instead, waving at the night porter in the lodge, who gave me an incredulous look fol owed by an encouraging thumbs-up.

With each slap of my feet on the sidewalk, some stiffness left my body. By the time they reached the gravel paths of the University Parks, I was breathing deeply and felt relaxed and ready for a long day in the library-no matter how many creatures were gathered there.

When I got back, the porter stopped me. "Dr. Bishop?"

"Yes?"

"I'm sorry about turning your friend away last night, but it's col ege policy. Next time you're having guests, let us know and we'l send them straight up."

The clearheadedness from my run evaporated.

"Was it a man or a woman?" I asked sharply.

"A woman."

My shoulders floated down from around my ears.

"She seemed perfectly nice, and I always like Australians. They're friendly without being, you know . . . "

The porter trailed off, but his meaning was clear.

Australians were like Americans-but not so pushy. "We did cal up to your rooms."

I frowned. I'd switched off the phone's ringer, because Sarah never calculated the time difference between Madison and Oxford correctly and was always cal ing in the middle of the night. That explained it.

"Thank you for letting me know. I'l be sure to tel you about any future visitors," I promised.

Back in my rooms, I flipped on the bathroom light and saw that the past two days had taken a tol . The circles that had appeared under my eyes yesterday had now blossomed into something resembling bruises. I checked my arm for bruises, too, and was surprised not to find any.

The vampire's grip had been so strong that I was sure Clairmont had broken the blood vessels under the skin.

I showered and dressed in loose trousers and a turtleneck. Their unal eviated black accentuated my height and minimized my athletic build, but it also made me resemble a corpse, so I tied a soft periwinkle sweater around my shoulders. That made the circles under my eyes look bluer, but at least I no longer looked dead. My hair threatened to stand straight up from my head and crackled every time I moved. The only solution for it was to scrape it back into a messy knot at the nape of my neck.

Clairmont's trol ey had been stuffed with manuscripts, and I was resigned to seeing him in Duke Humfrey's Reading Room. I approached the cal desk with shoulders squared.

Once again the supervisor and both attendants were flapping around like nervous birds. This time their activity was focused on the triangle between the cal desk, the manuscript card catalogs, and the supervisor's office. They carried stacks of boxes and pushed carts loaded with manuscripts under the watchful eyes of the gargoyles and into the first three bays of ancient desks.

"Thank you, Sean." Clairmont's deep, courteous voice floated from their depths.

The good news was that I would no longer have to share a desk with a vampire.

The bad news was that I couldn't enter or leave the library -or cal a book or manuscript-without Clairmont's tracking my every move. And today he had backup.

A diminutive girl was stacking up papers and file folders in the second alcove. She was dressed in a long, baggy brown sweater that reached almost to her knees. When she turned, I was startled to see a ful -grown adult. Her eyes were amber and black, and as cold as frostbite.

Even without their touch, her luminous, pale skin and unnatural y thick, glossy hair gave her away as a vampire.

Snaky waves of it undulated around her face and over her shoulders. She took a step toward me, making no effort to disguise the swift, sure movements, and gave me a withering glance. This was clearly not where she wanted to be, and she blamed me.

"Miriam," Clairmont cal ed softly, walking out into the center aisle. He stopped short, and a polite smile shaped his lips. "Dr. Bishop. Good morning." He raked his fingers through his hair, which only made it look more artful y tousled. I patted my own hair self-consciously and tucked a stray strand behind my ear.

"Good morning, Professor Clairmont. Back again, I see."

"Yes. But today I won't be joining you in the Selden End.

They've been able to accommodate us here, where we won't disturb anyone."

The female vampire rapped a stack of papers sharply against the top of the desk.

Clairmont smiled. "May I introduce my research col eague, Dr. Miriam Shephard. Miriam, this is Dr. Diana Bishop."

"Dr. Bishop," Miriam said cool y, extending her hand in my direction. I took it and felt a shock at the contrast between her tiny, cold hand and my own larger, warmer one. I began to draw back, but her grip grew firmer, crushing the bones together. When she final y let go, I had to resist the urge to shake out my hand.

"Dr. Shephard." The three of us stood awkwardly. What were you supposed to ask a vampire first thing in the morning? I fel back on human platitudes. "I should real y get to work."

"Have a productive day," Clairmont said, his nod as cool as Miriam's greeting.

Mr. Johnson appeared at my elbow, my smal stack of gray boxes waiting in his arms.

"We've got you in A4 today, Dr. Bishop," he said with a pleased puff of his cheeks. "I'l just carry these back for you." Clairmont's shoulders were so broad that I couldn't see around him to tel if there were bound manuscripts on his desk. I stifled my curiosity and fol owed the reading- room supervisor to my familiar seat in the Selden End.

Even without Clairmont sitting across from me, I was acutely aware of him as I took out my pencils and turned on my computer. My back to the empty room, I picked up the first box, pul ed out the leather-bound manuscript, and placed it in the cradle.

The familiar task of reading and taking notes soon absorbed my attention, and I finished with the first manuscript in less than two hours. My watch revealed that it was not yet eleven. There was stil time for another before lunch.

The manuscript inside the next box was smal er than the last, but it contained interesting sketches of alchemical apparatus and snippets of chemical procedures that read like some unholy combination of Joy of Cooking and a poisoner's notebook. "Take your pot of mercury and seethe it over a flame for three hours," began one set of instructions, "and when it has joined with the Philosophical Child take it and let it putrefy until the Black Crow carries it away to its death." My fingers flew over the keyboard, picking up momentum as the minutes ticked by.

I had prepared myself to be stared at today by every creature imaginable. But when the clocks chimed one, I was stil virtual y alone in the Selden End. The only other reader was a graduate student wearing a red-, white-, and blue-striped Keble Col ege scarf. He stared morosely at a stack of rare books without reading them and bit his nails with occasional loud clicks.

After fil ing out two new request slips and packing up my manuscripts, I left my seat for lunch, satisfied with the morning's accomplishments. Gil ian Chamberlain stared at me malevolently from an uncomfortable-looking seat near the ancient clock as I passed by, the two female vampires from yesterday drove icicles into my skin, and the daemon from the music reference room had picked up two other daemons. The three of them were dismantling a microfilm reader, the parts scattered al around them and a rol of film unspooling, unnoticed, on the floor at their feet.

Clairmont and his vampire assistant were stil stationed near the reading room's cal desk. The vampire claimed that the creatures were flocking to me, not to him. But their behavior today suggested otherwise, I thought with triumph.

While I was returning my manuscripts, Matthew Clairmont eyed me coldly. It took a considerable effort, but I refrained from acknowledging him.

"Al done with these?" Sean asked.

"Yes. There are stil two more at my desk. If I could have these as wel , that would be great." I handed over the slips.

"Do you want to join me for lunch?"

"Valerie just stepped out. I'm stuck here for a while, I'm afraid," he said with regret.

"Next time." Gripping my wal et, I turned to leave.

Clairmont's low voice stopped me in my tracks. "Miriam, it's lunchtime."

"I'm not hungry," she said in a clear, melodic soprano that contained a rumble of anger.

"The fresh air wil improve your concentration." The note of command in Clairmont's voice was indisputable. Miriam sighed loudly, snapped her pencil onto her desk, and emerged from the shadows to fol ow me.

My usual meal consisted of a twenty-minute break in the nearby bookstore's second-floor cafe. I smiled at the thought of Miriam occupying herself during that time, trapped in Blackwel 's where the tourists congregated to look at postcards, smack between the Oxford guidebooks and the true-crime section.

I secured a sandwich and some tea and squeezed into the farthest corner of the crowded room between a vaguely familiar member of the history faculty who was reading the paper and an undergraduate dividing his attention between a music player, a mobile phone, and a computer.

After finishing my sandwich, I cupped the tea in my hands and glanced out the windows. I frowned. One of the unfamiliar daemons from Duke Humfrey's was lounging against the library gates and looking up at Black-wel 's windows.

Two nudges pressed against my cheekbones, as gentle and fleeting as a kiss. I looked up into the face of another daemon. She was beautiful, with arresting, contradictory features-her mouth too wide for her delicate face, her chocolate brown eyes too close together given their enormous size, her hair too fair for skin the color of honey.

"Dr. Bishop?" The woman's Australian accent sent cold fingers moving around the base of my spine.

"Yes," I whispered, glancing at the stairs. Miriam's dark head failed to emerge from below. "I'm Diana Bishop."

She smiled. "I'm Agatha Wilson. And your friend downstairs doesn't know I'm here."

It was an incongruously old-fashioned name for someone who was only about ten years older than I was, and far more stylish. Her name was familiar, though, and I dimly remembered seeing it in a fashion magazine.

"May I sit down?" she asked, gesturing at the seat just vacated by the historian.

"Of course," I murmured.

On Monday I'd met a vampire. On Tuesday a witch tried to worm his way into my head. Wednesday, it would appear, was daemon day.

Even though they'd fol owed me around col ege, I knew even less about daemons than I did about vampires. Few seemed to understand the creatures, and Sarah had never been able to answer my questions about them. Based on her accounts, daemons constituted a criminal underclass.

Their superabundance of cleverness and creativity led them to lie, steal, cheat, and even kil , because they felt they could get away with it. Even more troublesome, as far as Sarah was concerned, were the conditions of their birth.

There was no tel ing where or when a daemon would crop up, since they were typical y born to human parents. To my aunt this only compounded their already marginal position in the hierarchy of beings. She valued a witch's family traditions and bloodlines, and she didn't approve of daemonic unpredictability.

Agatha Wilson was content to sit next to me quietly at first, watching me hold my tea. Then she started to talk in a bewildering swirl of words. Sarah always said that conversations with daemons were impossible, because they began in the middle.

"So much energy is bound to attract us," she said matter- of-factly, as if I'd asked her a question. "The witches were in Oxford for Mabon, and chattering as if the world weren't ful of vampires who hear everything." She fel silent. "We weren't sure we'd ever see it again."

"See what?" I said softly.

"The book," she confided in a low voice.

"The book," I repeated, my voice flat.

"Yes. After what the witches did to it, we didn't think we'd catch a glimpse of it again."

The daemon's eyes were focused on a spot in the middle of the room. "Of course, you're a witch, too. Perhaps it's wrong to talk to you. I would have thought you of al witches would be able to figure out how they did it, though.

And now there's this," she said sadly, picking up the abandoned newspaper and handing it to me.

The sensational headline immediately caught my attention: VAMPIRE ON THE LOOSE IN LONDON. I hurriedly read the story.

Metropolitan Police have no new leads in the puzzling murder of two men in Westminster.

The bodies of Daniel Bennett, 22, and Jason Enright, 26, were found in an al ey behind the White Hart pub on St Alban's Street early Sunday morning by the pub's owner, Reg Scott. Both men had severed carotid arteries and multiple lacerations on the neck, arms, and torso. Forensic tests revealed that massive loss of blood was the cause of death, although no blood evidence was found at the scene.

Authorities investigating the "vampire murders," as they were dubbed by local residents, sought the advice of Peter Knox.

The author of bestsel ing books on modern occultism, including Dark Matters: The Devil in Modern Times and Magic Rising: The Need for Mystery in the Age of Science, Knox has been consulted by agencies around the world in cases of suspected satanic and serial kil ings.

"There is no evidence that these are ritual murders," Knox told reporters at a news conference. "Nor does it seem that this is the work of a serial kil er," he concluded, in spite of the similar murders of Christiana Nilsson in Copenhagen last summer and Sergei Morozov in St Petersburg in the fal of 2007.

When pressed, Knox conceded that the London case may involve a copycat kil er or kil ers.

Concerned residents have instituted a public watch, and local police have launched a door-to-door safety campaign to answer questions and provide support and guidance.

Officials urge London residents to take extra precautions for their safety, especial y at night.

"That's just the work of a newspaper editor in search of a story," I said, handing the paper back to the daemon. "The press is preying on human fears."

"Are they?" she asked, glancing around the room. "I'm not so sure. I think it's much more than that. One never knows with vampires. They're only a step away from animals." Agatha Wilson's mouth drew tight in a sour expression. "And you think we're the unstable ones. Stil , it's dangerous for any of us to catch human attention."

This was too much talk of witches and vampires for a public place. The undergraduate stil had his earphones in, however, and al the other patrons were deep into their own thoughts or had their heads close to their lunch companions'.

"I don't know anything about the manuscript or what the witches did to it, Ms. Wilson. I don't have it either," I said hastily, in case she, too, thought I might have stolen it.

"You must cal me Agatha." She focused on the pattern of the carpet. "The library has it now. Did they tel you to send it back?"

Did she mean witches? Vampires? The librarians? I picked the likeliest culprits.

"Witches?" I whispered.

Agatha nodded, her eyes drifting around the room.

"No. When I was done with it, I simply returned it to the stacks."

"Ah, the stacks," Agatha said knowingly. "Everybody thinks the library is just a building, but it isn't."

Once again I remembered the eerie constriction I'd felt after Sean had put the manuscript on the conveyor belt.

"The library is whatever the witches want it to be," she went on. "But the book doesn't belong to you. Witches shouldn't get to decide where it's kept and who sees it."

"What's so special about this manuscript?"

"The book explains why we're here," she said, her voice betraying a hint of desperation. "It tel s our story- beginning, middle, even the end. We daemons need to understand our place in the world. Our need is greater than that of the witches or vampires." There was nothing addled about her now. She was like a camera that had been chronical y out of focus until someone came by and twisted the lenses into alignment.

"You know your place in the world," I began. "There are four kinds of creatures-humans, daemons, vampires, and witches."

"And where do daemons come from? How are we made? Why are we here?" Her brown eyes snapped. "Do you know where your power comes from? Do you?"

"No," I whispered, shaking my head.

"Nobody knows," she said wistful y. "Every day we wonder. Humans thought daemons were guardian angels at first. Then they believed we were gods, bound to the earth and victims of our own passions. Humans hated us because we were different and abandoned their children if they turned out to be daemons. They accused us of possessing their souls and making them insane. Daemons are bril iant, but we're not vicious-not like the vampires."

Her voice was clearly angry now, though it never lifted above a murmur. "We would never make someone insane.

Even more than witches, we're victims of human fear and envy."

"Witches have their share of nasty legends to contend with," I said, thinking of the witch-hunts and the executions that fol owed.

"Witches are born to witches. Vampires make other vampires. You have family stories and memories to comfort you when you're lonely or confused. We have nothing but tales told to us by humans. It's no wonder so many daemons are broken in spirit. Our only hope lies in brushing against other daemons one day and knowing we're like them. My son was one of the lucky ones. Nathaniel had a daemon for a mother, someone who saw the signs and could help him understand." She looked away for a moment, regaining her composure. When her eyes again met mine, they were sad. "Maybe the humans are right.

Maybe we are possessed. I see things, Diana. Things I shouldn't."

Daemons could be visionaries. No one knew if their visions were reliable, like the visions that witches had.

"I see blood and fear. I see you," she said, her eyes losing focus again. "Sometimes I see the vampire. He's wanted this book for a very long time. Instead he's found you. Curious."

"Why does Matthew Clairmont want the book?"

Agatha shrugged. "Vampires and witches don't share their thoughts with us. Not even your vampire tel s us what he knows, though he's fonder of daemons than most of his kind. So many secrets, and so many clever humans these days. They'l figure it out if we're not careful. Humans like power-secrets, too."

"He's not my vampire." I flushed.

"Are you sure?" she asked, staring into the chrome on the espresso machine as if it were a magic mirror.

"Yes," I said tightly.

"A little book can hold a big secret-one that might change the world. You're a witch. You know words have power. And if your vampire knew the secret, he wouldn't need you." Agatha's brown eyes were now melting and warm.

"Matthew Clairmont can cal the manuscript himself if he wants it so badly." The idea that he might be doing so now was unaccountably chil ing.

"When you get it back," she said urgently, grabbing my arm, "promise me you'l remember that you aren't the only ones who need to know its secrets. Daemons are part of the story, too. Promise me."

I felt a flicker of panic at her touch, felt suddenly aware of the heat of the room and the press of people in it.

Instinctively I searched for the nearest exit while focusing on my breathing, trying to curb the beginnings of a fight-or- flight response.

"I promise," I murmured hesitantly, not sure what it was I was agreeing to.

"Good," she said absently, dropping my arm. Her eyes drifted away. "It was good of you to speak with me." Agatha was staring at the carpet once more. "We'l see each other again. Remember, some promises matter more than others."

I dropped my teapot and cup into the gray plastic tub on top of the trash and threw away the bag from my sandwich.

When I glanced over my shoulder, Agatha was reading the sports section of the historian's discarded London daily.

On my way out of Blackwel 's, I didn't see Miriam, but I could feel her eyes.

The Selden End had fil ed with ordinary human beings while I was gone, al of them busy with their own work and completely oblivious to the creature convention around them. Envious of their ignorance, I took up a manuscript, determined to concentrate, but instead found myself reviewing my conversation in Blackwel 's and the events of the past few days. On an immediate level, the il ustrations in Ashmole 782 didn't seem related to what Agatha Wilson had said the book was about. And if Matthew Clairmont and the daemon were so interested in the manuscript, why didn't they request it?

I closed my eyes, recal ing the details of my encounter with the manuscript and trying to make some pattern of the events of the past few days by emptying my mind and imagining the problem as a jigsaw puzzle sitting on a white table, then rearranging the colorful shapes. But no matter where they were placed, no clear picture emerged.

Frustrated, I pushed my chair away from my desk and walked toward the exit.

"Any requests?" Sean asked as he took the manuscripts from my arms. I handed him a bunch of freshly fil ed-out cal slips. He smiled at the stack's thickness but didn't say a word.

Before leaving, I needed to do two things. The first was a matter of simple courtesy. I wasn't sure how they'd done it, but the vampires had kept me from being distracted by an endless stream of creatures in the Selden End. Witches and vampires didn't often have occasion to thank one another, but Clairmont had protected me twice in two days.

I was determined not to be ungrateful, or bigoted like Sarah and her friends in the Madison coven.

"Professor Clairmont?"

The vampire looked up.

"Thank you," I said simply, meeting his gaze and holding it until he looked away.

"You're welcome," he murmured, a note of surprise in his voice.

The second was more calculated. If Matthew Clairmont needed me, I needed him, too. I wanted him to tel me why Ashmole 782 was attracting so much attention.

"Perhaps you should cal me Diana," I said quickly, before I lost my nerve.

Matthew Clairmont smiled.

My heart stopped beating for a fraction of a second. This was not the smal , polite smile with which I was now familiar. His lips curved toward his eyes, making his whole face sparkle. God, he was beautiful, I thought again, slightly dazzled.

"Al right," he said softly, "but then you must cal me Matthew."

I nodded in agreement, my heart stil beating in erratic syncopation. Something spread through my body, loosening the vestiges of anxiety that remained after the unexpected meeting with Agatha Wilson.

Matthew's nose flared delicately. His smile grew a bit wider. Whatever my body was doing, he had smel ed it.

What's more, he seemed to have identified it.

I flushed.

"Have a pleasant evening, Diana." His voice lingered on my name, making it sound exotic and strange.

"Good night, Matthew," I replied, beating a hasty retreat.

That evening, rowing on the quiet river as sunset turned to dusk, I saw an occasional smoky smudge on the towpath, always slightly ahead of me, like a dark star guiding me home.