It was early evening, and the cloudless sky was transmuting from royal blue to a deep violet, with a smudge of fire orange and lime green over Paddington, four miles to the west, where, from Old Bailey's perspective anyway, the sun had recently set.
    _Skies,_ thought Old Bailey, in a satisfied sort of a way. Never a two of them alike. Not by day nor not by night, neither. He was a bit of a connoisseur of skies, was Old Bailey, and this was a good 'un. The old man had pitched his tent for the night on a roof opposite St. Paul's Cathedral, in the center of the City of London.
    He was fond of St. Paul's, and it, at least, had changed little in the last three hundred years. It had been built in white Portland stone, which had, before it was even completed, begun to turn black from the soot and the filth in the smoky London air and now, following the cleaning of London in the 1970s, was more or less white again; but it was still St. Paul's. He was not sure that the same could be said for the rest of the City of London: he peered over the roof, stared away from his beloved Sky, down to the sodium-lit pavement below. He could see security cameras affixed to a wall, and a few cars, and one late office worker, locking a door and then walking toward the Tube. _Brrr._ Even the thought of going underground made Old Bailey shudder. He was a roof-man and proud of it; had fled the world at ground level so long ago . . .
    Old Bailey remembered when people had actually _lived_ here in the City, not just worked; when they had lived and lusted and laughed, built ramshackle houses one leaning against the next, each house filled with noisy people. Why, the noise and the mess and the stinks and the songs from the alley across the way (then known, at least colloquially, as Shitten Alley) had been legendary in their time, but no one lived in the City now. It was a cold and cheerless place of offices, of people who worked in the day and went home to somewhere else at night. It was not a place for living anymore. He even missed the stinks.
    The last smudge of orange sun faded into nocturnal purple. The old man covered the cages, so the birds could get their beauty sleep. They grumbled, then slept. Old Bailey scratched his nose, after which he went into his tent and fetched a blackened stew-pot, some water, some carrots and potatoes, salt, and a well-hanged pair of dead, plucked starlings. He walked out onto the roof, lit a small fire in a soot-blackened coffee can, and was putting his stew on to cook when he became aware that someone was watching him from the shadows by a chimney stack.
    He picked up his toasting fork and waved it threateningly at the chimney stack. "Who's there?"
    The marquis de Carabas stepped out of the shadows, bowed perfunctorily, and smiled gloriously. Old Bailey lowered his toasting fork. "Oh," he said. "It's you. Well, what do you want? Knowledge? Or birds?"
    The marquis walked over, picked a slice of raw carrot from Old Bailey's stew, and munched it. "Information, actually," he said.
    Old Bailey chortled. "Hah," he said. "There's a first. Ehh?" Then he leaned toward the marquis. "What'll you trade for it?"
    "What do you need?"
    "Maybe I should do what you do. I should ask for another favor. An investment for one day down the road." Old Bailey grinned.
    "Much too expensive, in the long run," said the marquis, without humor.
    Old Bailey nodded. Now the sun had gone down, it was getting very cold, very fast. "Shoes, then," he said. "And a balaclava hat." He inspected his fingerless gloves: they were more hole than glove. "And new gloveses. It's going to be a bastard winter."
    "Very well. I'll bring them to you." The marquis de Carabas put his hand into an inside pocket and produced, like a magician producing a rose from thin air, the black animal figure he had taken from Portico's study. "Now. What can you tell me about this?"
    Old Bailey pulled on his glasses. He took the object from de Carabas. It was cold to the touch. He sat down on an air-conditioning unit, then, turning the black obsidian statue over and over in his hand, he announced: "It's the Great Beast of London." The marquis said nothing. His eyes flickered from the statue to Old Bailey, impatiently. Old Bailey, enjoying the marquis's minor discomfort, continued at his own pace. "Now, they say that back in first King Charlie's day--him 'as got his head all chopped off, silly bugger--before the fire and the plague, this was, there was a butcher lived down by the Fleet Ditch, had some poor creature he was going to fatten up for Christmas. Some says it was a piglet, and some says it wusn't, and there's some--and I list meself as one of them--that wusn't never properly certain. One night in December the beast runned away, ran into the Fleet Ditch, and vanished into the sewers. And it fed on the sewage, and it grew, and it grew. And it got meaner, and nastier. They'd send in hunting parties after it, from time to time."
    The marquis pursed his lips. "It must have died three hundred years ago."
    Old Bailey shook his head. "Things like that, they're too vicious to die. Too old and big and nasty."
    The marquis sighed. "I thought it was just a legend," he said. "Like the alligators in the sewers of New York City."
    Old Bailey nodded, sagely. "What, the big white buggers? They're down there. I had a friend lost a head to one of them." A moment of silence. Old Bailey handed the statue back to the marquis. Then he raised his hand and snapped it, like a crocodile head, at de Carabas. "It was okay," gurned Old Bailey with a grin that was most terrible to behold. "He had another."
    The marquis sniffed, uncertain whether or not Old Bailey was pulling his leg. He made the statue of the Beast vanish inside his coat once more.
    "Hang on," said Old Bailey. He went back inside his brown tent and returned holding the ornate silver box the marquis had given him on their previous meeting. He held it out to the marquis. "How about this then?" he asked. "Are you ready to take it back? It fair gives me the creepy shivers, having it around."
    The marquis walked to the edge of the roof, dropped the eight feet to the next building. "I'll take it back, when all this is over," he called. "Let us hope that you don't have to use it."
    Old Bailey leaned over. "How will I know if I do?"
    "You'll know," called the marquis. "And the rats will tell you what to do with it." And with that he was over the side of the building, slipping down, using drainpipes and ledges as handholds.
    "Hope I never finds out, that's all I can say," said Old Bailey to himself. Then a thought struck him. "Hoy," he called out to the night and the City. "Don't forget the shoeses and the gloveses!"

    The advertisements on the walls were for refreshing and health-giving malted drinks, for two-shilling day excursions by train to the seaside, for kippered herrings, moustache wax and bootblack. They were smoke-blackened relics of the late twenties or the early thirties. Richard stared at them in disbelief. It seemed completely abandoned: a forgotten place. "It _is_ British Museum Station," admitted Richard. "But . . . but there never _was_ a British Museum Station. This is all wrong."
    "It was closed down in about 1933, and sealed off," said Door.
    "How _bizarre_," said Richard. It was like walking through history. He could hear trains echoing through tunnels nearby, felt the push of air as they passed. "Are there many stations like this?"
    "About fifty," said Hunter. "They aren't all accessible, though. Not even to us."
    There was a movement in the shadows at the edge of the platform. "Hello," said Door. "How are you?" She went down into a crouch. A brown rat stepped out into the light. It sniffed at Door's hand.
    "Thank you!" said Door, cheerfully. "I'm glad _you_ aren't dead, too."
    Richard edged over. "Um, Door. Could you tell the rat something for me?"
    The rat turned its head toward him. "Miss Whiskers says that if there's anything you've got to say to her, you can tell it to her yourself," said Door.
    "Miss Whiskers?"
    Door shrugged. "It's a literal translation," she said. "It sounds better in rat."
    Richard did not doubt it. "Um. Hello . . . Miss Whiskers . . . Look, there was one of your rat-speaker people, a girl named Anaesthesia. She was taking me to the market. We were crossing this bridge in the dark, and she just never made it across."
    The rat interrupted him, with a sharp _squee._ Door began to talk, hesitantly, like a simultaneous translator. "She says . . . that the rats do not blame you for the loss. Your guide was . . . mm . . . taken by the night . . . as tribute."
    "But--"
    The rat squeaked again. "Sometimes they come back . . . " said Door. "She has taken note of your concern . . . and thanks you for it." The rat nodded to Richard, blinked her bead-black eyes, then leapt to the floor and scurried back into the dark. "Nice rat," said Door. Her disposition seemed to have improved remarkably, now that she had the scroll. "Up there," she said, indicating an archway effectively blocked by an iron door.
    They walked over to it. Richard pushed against the metal, but it was locked from the other side. "Looks like it's been sealed up," said Richard. "We'll need special tools."
    Door smiled, suddenly; her face seemed to be illuminated. For a moment, her elfin face became beautiful. "Richard," she said. "My family. We're openers. It's, our Talent. Look . . . " She reached out a grubby hand, touched the door. For a long moment nothing happened, then there was a loud crash from the other side of the door, and a _chunk_ from their side. Door pushed against the door and, with a fierce squeal from the rusted hinges, it opened. Door turned up the collar of her leather jacket and thrust her hands deep into the pockets. Hunter shone her flashlight into the blackness beyond the doorway: a flight of stone steps, going up, into the dark. "Hunter. Can you take the rear?" asked Door. "I'll go on in front. Richard can take the middle."
    She walked up a couple of steps. Hunter stayed where she was. _"Lady?"_ said Hunter. "You are going to London Above?"
    "That's right," said Door. "We're going to the British Museum."
    Hunter bit her lower lip. Then she shook her head. "I must stay in London Below," she said. There was a tremble in her voice. Richard realized that this was the first time he had ever seen Hunter display any emotion other than effortless competence or, occasionally, tolerant amusement.
    "Hunter," said Door, bewildered. "You're my bodyguard."
    Hunter looked ill at ease. "I am your bodyguard in London Below," she said. "I cannot go with you to London Above."
    "But you have to."
    "My lady. I cannot. I thought you understood. The marquis knows." _Hunter will look after you as long as you stay in London Below,_ thought Richard. _Yes._
    "No," said Door, her pointed chin pushed out and up, her odd-colored eyes narrowed. "I don't understand. What is it?" she added, scornfully. "Some kind of curse or something?" Hunter hesitated, licked her lips, then nodded. It was as if she were admitting to having some socially embarrassing disease.
    "Look, Hunter," Richard heard his own voice saying, "don't be silly." For a moment he thought she was about to hit him, which would have been bad, or even to start crying, which would have been much, much worse. Then she took a deep breath, and said, in measured tones, "I will walk by your side when you are in London Below, my lady, and I shall guard your body from all harm that might befall you. But do not ask me to follow you to London Above. I cannot." She folded her arms beneath her breasts, planted her legs a little apart, and looked for all the underworld like a statue of a woman not going anywhere, cast in brass and in bronze and in burnt caramel.
    "Right," said Door. "Come on, Richard." And she set off up the steps.
    "Look," said Richard. "Why don't we stay down here? We can find the marquis, and then all set off together, and--" Door was disappearing into the darkness above him. Hunter was planted at the foot of the stairs.
    "I shall wait here until she returns," Hunter told him. "You may go, or stay, as you will."
    Richard chased up the steps, as fast as he could, in the dark. Soon he saw Door's lamp-light above him. "Wait," he panted. "Please." She stopped, and waited for him to catch up. And then, when he had caught up, and was standing next to her on a claustrophobically small landing, she waited for him to catch his breath. "You can't just go running off like that," said Richard. Door said nothing; the line of her lips became slightly more compressed; the angle of her chin was ever-so-slightly raised. "She's your bodyguard," he pointed out.
    Door began to walk up the next flight of steps. Richard followed her. "Well, we'll be back soon enough," said Door. "She can start guarding me again then."
    The air was close, dank and oppressive. Richard wondered how you could tell if the air was bad, in the absence of a canary, and he contented himself with hoping that it wasn't. "I think the marquis probably did know. About her curse, or whatever it is," he said.
    "Yes," she said............