It was nearly three in the morning, and the windows of Horace Blaydon's tall brown-brick house on Queen Anne Street were dark.

"Can you hear anything?" Asher whispered, from the shelter of the comer of Harley Street. "Anyone within?"

Ysidro bowed his head, colorless hair falling down over his thin fea-tures in the glow of the street lamp, his heavy-lidded eyes shut. The silence in this part of the West End was profound, sunk deep in the sleep of the well-to-do and self-justified who knew nothing of vampires be-yond the covers of yellow-backed penny dreadfuls and gave little thought to how their government got its information about the Ger-mans. The rain had ceased. In an alley, two cats swore at one another- lovers or rivals in love-and there was the smallest flicker of Ysidro's head as he moved to listen and to identify.

At length he whispered, "It's difficult to tell at this distance. Cer-tainly there's no one in the upper part of the house, though servants sometimes have rooms in the cellars."

"It has to be here," Asher breathed. "His country place has been closed up for years and it's a good thirty miles as the crow flies. He's a research pathologist-he doesn't have a consulting practice to worry about. His wife died some years ago and his son's in the Life Guards. It wouldn't be difficult to keep him away on some pretext. He's not very bright."

"He would have to be intensely stupid," Ysidro murmured, "not to notice, if his father were forced into such an alliance as I forced you."

Asher flattened to the corner of the house and scanned the empty street. "Set your mind at rest."

It was difficult to tell whether the soft sound in the darkness was a comment or a laugh. "You know this Blaydon," Ysidro then said softly.

"Is it likely we could win him to our side-turn him, as is said in the parlance of your Foreign Office?"

"It depends on what his partner's told him." The street before them was still. The lamplight gleamed like fractured metal on the water of the gutters. If Ysidro, turning his head slightly for what even the cob-web nets of his far-flung awareness failed to bring him, could hear nothing, it stood to reason Asher wouldn't, either. But still, Asher's every nerve strained to hear. "I never knew Blaydon well-I went to fetch Lydia at some of his lectures and had been to the Peaks a few times. I think he was piqued that I'd married the Willoughby fortune instead of letting his son do it, but I don't think he held it against me the way Dennis did. Horace is a stiff-backed and self-righteous old bigot, but he's honest. He was one of the few dons who stood up to Lydia's father when he wanted her taken out of University-though, of course, at the time Horace had a stake in wanting her to stay.

"In his place-the vampire's, I mean-I'd make damn sure he thought the Limehouse rampages were the work of the vampires we were tracking."

"You think he'd believe that?"

"I think if Dennis were in danger-if the vampire were threatening Dennis' life as you're threatening Lydia's to win my compliance-he'd want to. We did it in the Department all the time. The old carrot-and-stick routine: on the one hand Dennis' life is in danger; on the other, Blaydon can do viral research with what blood he can take, and con-gratulate himself on killing vampires at the same time. He may not even know Lydia's a prisoner or he may know there is a prisoner, but not that it's Lydia. It's surprising how ignorant the right hand can be when it would really rather not know what the left hand is doing,"

They left the shelter of the corner and glided back like specters through the wet blackness of deep night in October London. "The mews is just past the next street," Ysidro murmured, barely audible even in the utter silence of the empty street. "Do you plan to speak to this Blaydon, then?"

"If I can," Asher replied, as they slipped into the cobbled, horse-smelling canyon of the mews. "After I get Lydia out of this, and see how the land lies, if possible. Like Lydia-like a lot of people in the medical profession-Horace has a little streak of saintmanqut in him, in his case one of the stiffer-backed Scots variety. It could be the vam-pire is playing on that as well."

"I would give a good deal to know who it is." The vampire's touch was light on his elbow, guiding him around half-seen obstacles. What little lamplight filtered in from the street glistened on the puddles in the center of the lane, but left the sides in velvet shadow; the air was sweet with the clean smell of hay and the pungency of well-tended horses, prosaic odors and comforting. "I suspect Calvaire came to London to seek in him a partner in power, but I still find it strange that he would have heard of him at all when I had not, much less been able to locate him."

"Perhaps Brother Anthony told him whom to look for and where to look."

"Maybe." Ysidro's voice was absolutely neutral, but Asher, who was growing used to the tiniest nuances of his speech, had the impression he was not satisfied. "There are many things here which I do not under-stand, and among them is why Calvaire's appearance on the scene should have triggered these murders-if it did trigger them, and all these matters are not simply a chance juxtaposition in time. It may be that your Mistress Lydia can enlighten us, when we find her, or Blaydon. As I recall, Tulloch the Scot was big, though not so big as you describe. Your height, but bulkier..."

"No," Asher said. "I looked up at him-he came over the top of me like a wave."

They moved down the darkness of the mews, scanning the tall, regu-lar cliff of houses visible beyond the stables and cottages. All were dark; it was the ebb-tide hour of the soul. He went on softly, "But conceivably this virus, this mutation, could trigger abnormal growth. It could..."

The vampire beside him checked, and the slim hand tightened on his arm; turning his head swiftly, Asher caught the glint of the luminous eyes.

"What is it?"

The vampire moved a finger, cautioning. For a time, he listened like a hunted man for sounds which he thought he might have heard. Then he shook his head, though his eyes did not relax.

"Nothing." The word was more within Asher's head than without. In a stable, a horse wickered and stamped sleepily. "I-all of us-have grown used to the idea that as vampires we are, barring acts of violence, immortal, and to the idea that acts of violence are all we need fear. Like Lemuel Gulliver, we were stupidly willing to believe 'immortal' means 'safe from change.' It is disconcerting to learn that there may be terms to that bargain after all."

Asher felt awkwardly in the pockets of his ulster for the reassuring weight of Lydia's revolver, which, like the one the police had confis-cated from him, was loaded with silver bullets-it was astounding what one could purchase at hyperfashionable West End gunsmiths. He'd also brought both silver knives and even the little hypodermic kit with its ampoules of silver nitrate. He'd found bills from Lambert's, for silver chains and at least one silver letter opener, stuffed into the medical journals as bookmarks, so she hadn't gone out completely unarmed. His own silver chains lay slim and cold over the half-healed bites on his throat and left wrist-the right was muffled in sling and splints and puffed up to twice its normal size-but even so, he felt hopelessly out-gunned.

The briefest of investigations revealed a brougham and a trim bay hack with one white foot in Blaydon's stables. After a moment's silent listening, Ysidro murmured, "No one in the quarters upstairs, though someone has lived here recently-not more than a few months ago." "He'd have turned off the servants," Asher breathed in return. From the stable's rear door, they could see the tall back of the house, past the few bare trees and the naked shrubs of a narrow town garden. "You can't hear whether someone's in the cellar?"

Simon's eyes never moved from the house, but Asher could tell he was listening all around him and behind nun, just the same. The night seemed to breathe with unseen presence, Asher's hair prickled with the certainty that somewhere nearby they were being watched; that some-thing listened, as Ysidro was listening, for his single breath and the beat of his solitary heart. By mutual consent, they both backed out of the small stable and into the lane again, where a sound, a commotion, was likely to bring every coachman and dog on the mews.

"I'm going in." Asher shrugged his arm clear of his ulster; Ysidro caught it and lowered it to the baled hay piled just outside the stable door. With his left hand, Asher fumbled the revolver and a silver knife from the pocket, transferred the revolver to his corduroy jacket; the knife-since he was wearing shoes rather than boots-slid conveniently into his sling. "Can you watch my back?"

"Don't be a fool." Simon slipped his black Inverness from his shoul-ders, laid it in a soft whisper of velvet-handed wool on the hay, and reached into Asher's jacket pocket for the revolver. He patted the cylin-der gingerly a few times with his other hand, like a man testing for heat inside. Satisfied, he concealed it in his own jacket. "If you had four hours' sleep on the boat from Calais last night, I should be surprised. No, stay here-you should be fairly safe. A cry from you-a sound from you-will wake every groom and dog in the mews, and this vam-pire must remain unsuspected now for his very life."

And he was gone, in a momentary blink of distracted consciousness that made Asher curse his own lapse of guard.

He was aware that the vampire was right, however. The strain of the night was telling on him. It would have done so, even had his body not been struggling with the aftereffects of his attack by the Paris vampires or with the shock of the struggle at Grippen's and the pain of his broken hand. The novocaine was beginning to wear off, and his arm in its sung throbbed damnably at every step he took. That alone would be enough to disrupt the concentration that was still his only possible defense against the ancient vampire's soundless approach.

He was conscious, too, of what Ysidro was doing for him. The vam-pire, though visibly edgy-or as visibly edgy as Ysidro ever got- throughout the walk down the silent streets from Bruton Place to Queen Anne Street, had never seemed to consider the option of not accompanying him. Perhaps it was simply because he knew that Asher would neither abandon his search for Lydia, nor have the strength to defeat the killer alone, should he meet it. But Asher suspected that, like the oddly gentle charm of his faded and cynical smile, the honor of an antique nobleman lingered in him still. He might be arrogant and high-handed and be, as Lydia had blithely calculated, a murderer thousands of times over, but he would not abandon his responsibilities to his liege man or his liege man's wife. This was more than could be said of Grippen or the Farrens, who had informed him, with varying degrees of tact, that the location of new boltholes for themselves took absolute precedence over any possible fate of Lydia's.

And all of this, in spite of the ironic fact that Simon could not even touch the problematical protection of a silver chain.

If Lydia could root out all-or almost all-of the vampires' hiding places, Asher thought, settling himself back on the hay bales and draw-ing his ulster clumsily up over his shoulders again, there was a good chance Blaydon and whatever vampire he was working with could do so, too, particularly if Calvaire had revealed any information to his prospective partner in power as to their whereabouts. He wondered whether he himself could remain awake to mount guard over whatever blown refuge Ysidro would be forced to take come dawn. Fatigue weighed down his mind, and he fought to keep it clear. He doubted his ability, even if Simon would admit him to the place...

A man's hacking, tubercular cough snapped him out of sleep with cold sweat on his face. Whirling, clawing at his pocket for the revolver he recalled a split-second later Ysidro had taken, he saw it was just a stableman, ambling back from a privy at the end of the mews. A dog barked. Lights were on in one or two of the coachmen's rooms above the stables. The smell of dawn was in the air.

Heart pounding, breath coming fast with interrupted sleep, Asher fumbled for his watch.

By the reflected radiance of those few lanterns now burning in coach house and cottage windows, he saw it was nearly five. Beside him on the hay, Simon's black cloak still lay like a sleeping animal. Small and cold, something tightened down inside of him. It was, of course, possible that the vampire had simply abandoned Asher and the cloak and gone to ground somewhere when he sensed the far-off approach of the day.

Asher did not for a moment believe this. Dread sank through him like a swallow of poison. Dawn was getting close.

Over the years, Asher had picked up a fine selection of curses in twelve living and four dead languages, including Basque and Finno-Ugric. He repeated them all as he slid the ulster from his shoulders, left it draped like a corpse over the hay, and slipped through the close, dark warmth of the stable and into Blaydon's back garden.

Exhaustion was fighting the screaming of every nerve in his body as he stood for a moment knee-deep in sodden weeds, looking up at that silent house. He wondered if it was imagination, or if there was the faintest glow of light in the dark sky and if the few outbuildings, the glass-paned extension that comprised the kitchen, and the dripping, naked tree seemed clearer than they had? He was straining with spent nerves and clouded senses to catch sight of the invisible, to pick up footfalls which even to vampires were inaudible, to be aware of what-ever it was he sensed, drifting like the passage of a diffuse shadow through the darkness of the mews behind him.

How much daylight could a vampire of Simon's age stand? How long before his flesh would ignite like a torch?

The silver knife in his left hand, he slipped toward the looming black wall of the house.

There was a street lamp nearby, and enough light filtered down for him to make out that the kitchen was deserted, as was the breakfast room whose window looked out onto the garden. The cellar had two windows, just at ground level; they were closed, but not barred or even latched. The hackles prickled on his neck at the mere thought of going into that house.

He stepped back into the yard, looking up at the first-floor windows above. Even from here, he thought that the one over the kitchen was barred.

He was shivering all over now, the predawn darkness seeming to press on him with whispering threat. Like Hyacinthe, he thought, who could summon him to open his barred retreat to her, though the sane part of his mind knew she would kill him when he did. But there was no time, now, to do anything else.

Empty crates, dark with dampness and bearing the stenciled names of various purveyors of scientific equipment, had been stacked near the kitchen door. Cursing in the remoter Slav tongues, Asher hooked his good hand around a drain pipe and used the crates to help himself up to the windows above.

The nearer window, open a slit at top and bottom, showed him the dark shapes of a workbench and the glint of glass; from it drifted a fetid reek which repulsed him, a whiff of chemicals underlain by the stink of organic rot. Beneath the barred window was only an ornamental ledge, and he exercised a number of plain Anglo-Saxon monosyllables as he disengaged his broken hand from its sling and hooked the tips of his swollen fingers over the grimy brickwork to edge himself along. At least, he thought wryly, this was one place where heknew the ancient vampire, the Plague vampire-if Plague it was-couldn't sneak up on him from behind. It was small comfort.

The room behind the bars was very small, an extension, like the kitchen below it, added onto the house after its original construction, and bare save for a single coffin in its center. The glow from the mews nearby dimly showed the coffin itself closed. Asher couldn't be sure in the dark-moreover there was a pane of glass between his face and the bars-but he thought the bars themselves had a silvery gleam in the faint twilight of coming dawn.

In twenty minutes it was going to be too late to do anything.

Worn out, Asher leaned his forehead against the wet glass. More than he had ever done, even in the darkness of the Paris alley with Grippen's teeth in his throat, he wished he was back in Oxford, in bed with Lydia, with nothing more to look forward to than buttered eggs for breakfast and another day of dealing with undergraduate inanities. Whether Hor-ace Blaydon was in the house or not-and he might have been in the cellar, waiting-there was no telling where the vampire was.

But even as the thought went through Asher's mind, he was easing himself back along the slimy ledge to the laboratory window. He, at least, could combat the thing with silver, something Ysidro was ironi-cally helpless to do. But that, of course, was the reason the vampire had employed him in the first place.

His heart beat quicker at the thought of Lydia. The hostages thatmortals give to fortune, Ysidro had said of the red-haired girl then lying deathlike in their unnaturally silent house.

The laboratory window yielded silently to his gentle touch. Did the ancient vampire report home for the day? Was that, in fact, its coffin, protected from the other vampires by the silver bars on the window, as Asher had been protected in Paris by the silver lock on the door? But in that case, why avoid the daylight?

It crossed his mind, as he eased himself through the window into the dark laboratory, to wonder how much Dennis knew about what was going on, and if he could somehow turn that young man's raging energy and love for Lydia to good account. It was unlikely that Blaydon's partner was holding him hostage somewhere-physically to hold some-one prisoner required a great deal of time, care, and energy, as Ysidro undoubtedly knew. Asher could probably find Dennis at his rooms at the Guards' Club... The thought lasted rather less time than a rip-ple on a very small pond. Though he doubted Blaydon had informed his son of what was going on, it was only because the pathologist was shrewd enough to realize that Dennis' stupid impulsiveness would make him a useless ally for either side.

The smell in the laboratory was foul, with an under-reek of rotting blood. Gritting his teeth, Asher lifted his right hand back into its damp and filth-splotched sling with his left. He felt his way around the wall, where the floor would be less likely to creak, his fingers gliding over the surfaces of tables, chairs, and cabinets. The door at the far side of the room opened without a sound.

So far, so good. If the vampire was here, watching him in visibly from the darkness, this was all useless, of course; the pounding of his heart alone sounded loud enough for even mortal ears to hear. But he did not know whether the creature was here, and on his silence his life and Ysidro's might depend.

How much time? he wondered. How much light?

The door of that small room over the kitchen was reinforced with steel and massively bolted from the outside. The bolt made the faintest of whispered clicks as he eased it over. Beyond, in the wan glow of the street lamp somewhere outside, the room lay bare and empty, except for the closed coffin.

Arizona Landscape with Apaches, he thought, remembering the old Indian-fighter's sketch. He took a deep breath and strode swiftly, si-lently, across to the coffin's side.

The sky beyond the barred window was distinctly lighter than it had been. They'd have to run for cover, he thought-after three hundred and fifty years, Ysidro would doubtless know every bolthole in Lon-don

If it were Ysidro, and not the day stalker, who lay in that coffin.

The lid was heavy and fitted close. It was an effort to raise it with one hand. As Asher lifted it clear, Ysidro turned and flinched, trying to shield his face with his shirt-sleeved arms, his long, ghostly hair tan-gling over the coffin's dark lining beneath his head. "No..."

Behind him, Asher heard the door close and the bolts slide home. He was too tired, too spent, even to curse; he had thrown on the longest of long shots and lost.

"Close it." The long fingers that covered the vampire's eyes were shaking; beneath them Asher could see the white-lashed eyes shut in pain. The light voice was sunk to a whisper, shivering, like his hands, under the strain of exhaustion and despair, "Please, close it. There is nothing we can do."

Knowing he was right, Asher obeyed. Whether he had been brought here forcibly, lured, or driven, once the doors had been locked behind him, there was literally nothing Don Simon could have done but take the only refuge available against the coming daylight. He slumped, bracing his back against the casket, knowing he should keep watch and knowing there wasn't a hope in the nine circles of Hell of his being able to remain awake to do so.

He was asleep before the first sunlight came into the room.