Celestia stepped up to the door, composed herself, and knocked twice. The door swung inward, revealing a room the size of an aircraft hangar.
The floor was more smooth stone, thousands of square yards of it, so polished and level that you could set a basketball down anywhere at all and it wouldn't roll a millimeter. The room, if 'room' could be applied to something so large that being in it felt like being outside, was also a mess. Rough cubes of various metals, mostly copper, bronze, brass, that kind of thing, lay scattered and stacked with no system of organization or eye for decor. Scrap and wreckage littered the floor as well, piles of steel shingles or scales, drifts of iron leaves, mounds of speckled wood ash and an apparently limitless array of other absent-minded arrangements of debris, waste, and raw material were all strewn around the space.
At the center of the room there was a worktable taller than a two-story building, and behind the worktable stood a giant.
He looked like a stocky human more than anything else, but with no eyes or eye sockets, and too many fingers with too many joints. He wore an apron of some kind of thick, stiff cloth, and something like pants. He was enormous.
Some tiny metallic thing fluttered down from the distant rafters of the room and landed on the giant's shoulder. The giant turned to it for a moment and turned back.
The giant spoke. His voice was so inhumanly deep that some syllables were simply too low for Mag's ears to register. "Cordial greetings to you, glorious one. You have chosen to make your presence known in the proper way, I see, but elected to let your most honorable sister wander. Do you plan to distract me while she digs through my collection?"
"I am here," said Luna.
"Oh? But is that not a mortal voice I hear?"
Then Celestia and Luna told their story. Mag noticed she didn't merit an introduction, not that she had any problem with that at all. She also noticed Celestia and Luna told the story very differently than they'd told it to Mag. The content was the same, but the delivery was fact-filled, unemotional, and full of precise language. Events were almost unrecognizable. Celestia had calmly observed the end of her world, checked her watch, proceeded briskly to a hospitable world, and made camp. After resting, she went back to Equestria to more closely examine its remains -
"Why did you not examine them while you were there the first time?" said the giant, whose title was apparently "sculptor," or "milord" if you were feeling familiar.
"I preferred to consider the situation in a more comfortable place, so I left as soon as I felt able," said Celestia.
Back in Equestria, Luna entered the mind of a mortal -
"Why did you bring a mortal with you to Equestria?" said the sculptor.
"My own reasons," said Celestia.
- and then the three of them returned to camp. Neither Celestia nor Luna mentioned Earth, humans, or any detail on where they'd set up.
The sculptor noticed this. "What are you not telling me?"
"I think we've covered every relevant detail," said Celestia.
"For instance, you didn't provide a name for your mortal."
"This is Mag Wilson," said Celestia.
Well, there was the introduction. She would have to make the best of it. "Hiya, uh, milord."
"And what are you?" said the sculptor.
"A white human woman."
The thing on his shoulder fluttered. "Your first lie," said the sculptor. "I'm told you are brown, not white."
"It's just an expression. It means my skin is paler than some peoples'. Milord."
"Oh, a metaphor," said the sculptor disdainfully.
"I'll try to warn you next time I'm about to use one."
"Or you could be silent," said the sculptor.
"Yessir." This was not the time to start a fight.
The giant rested his strange hands on the table, palms down. He didn't look in her direction, but then again, he had no eyes. "I have taken up the responsibility of keeping a collection of dangerous devices, ideas, and knowledge here my world, with the aim of learning to counter them, or, in some cases, to suppress them. Yes, sometimes I work to suppress the transmission of dangerous ideas between the worlds. My collectors know which books they must collect from travelers, what thoughts must be kept in quarantine in the worlds in which they belong. Mortal, can you guess which world produces the greatest number of things I must ban? You may speak."
"Humans," said Mag.
"Earth," said the sculptor.
"Yes, sir."
He shook his head. "I would say you are not welcome here, human, but how can I? So many of the things here belong to humanity that some parts of my world look like an outpost of Earth, even though you so rarely venture out of your mirrors. Tell me, when your species makes war, does it still light wild boars on fire and chase them into the enemy?"
"No, we mostly just drop explosives out of flying machines. It's more efficient. Sir."
"So I've read," said the sculptor. "Princesses, your majesties, I cannot help you at this time. You look for knowledge. For our purposes, we might separate the knowledge in my possession into two categories: those which humans have found, and those which humans have not found. As for the first, it would be useless to give you information you can as easily get from your human friends, and as for the second, I have no intention of putting yet more dangerous information within their reach. However, once the mortal has died and Luna is free, if you leave the human world and swear not to return to Earth with the information you glean here, whatever it may be, I will give you access to my archives. Good day." He started fiddling with some tiny metallic thing on his worktable.
Celestia blinked a couple of times but didn't move. "Lord sculptor, I consider myself a good judge of character. Knowing my reputation, would you agree?"
"No, I wouldn't. I heard about that 'Nightmare Moon' incident. Now Princess Luna stands in front of me, such as she is, walking free and more or less alive. This is not an acceptable risk. If you had sense, you would leave her here."
Celestia's features went hard. She opened her mouth to speak. Mag, remembering what Celestia had said to the eldest when he'd brought up the subject of Nightmare Moon, decided to jump in.
"Your sculptorness, what if I asked if we could see the books in your human section?"
"Who is spea - oh, the mortal again. Why do you want to see the human library? Everything there is already known to your people."
Mag gave the sculptor her best smile and then remembered he was blind, and that he would be unlikely to appreciate a smile anyway. "We humans know all kinds of things we don't tell each other. I'll bet one of us knew something about magic at some point in history, and, from the sounds of it, there are probably copies of that person's notes."
He frowned a colossal frown. "Human books of dark magic? I have more than you two can carry." Now Mag smiled for real. "And as the books are the property of your people, and you are an individual of good standing with my library except insofar as you are human, the rules I live by insist that I give you what is yours if you ask for it. What sort of dark magic books are you looking for? No, you needn't tell me. I overheard Celestia earlier. Planar curses, existential weapons, supercosmological phenomena, the practical effects of paradoxes, and similar topics."
"Exactly," said Mag.
"I believe I have something," said the sculptor. Mag winked at Celestia. Celestia smiled gratefully but looked worried.
***
Mag had wondered what nonmagical books the sculptor was likely to ban. User manuals to modern military ordinance seemed like a good bet. The more poisonous political or social philosophies, such as eugenics and imperialism, would certainly be there. Mag held a private hope that there would be a wide variety of religious works as well. The thought of keeping Christianity quarantined to one world suited her just fine.
Judging by the size of the Underlake library of human written works, the sculptor didn't seem to approve of human books in general. The books were held in one room, but the boxes and shelves and piles and drifts and mountain ranges of books were so tall that even the sculptor needed a ladder, and the room was so wide that it would take him several minutes to jog across it.
These were the general facts of the place. The specifics evaded her. She was too dazed to think, because the sculptor had carried her there on his shoulder.
She would have preferred to walk, but the library was far too far away. Celestia couldn't teleport her because the sculptor had banned teleportation in his world so as to keep visitors under control. He suggested that Mag ride on Celestia's back. Mag and Celestia said "No" at the same time, and Celestia announced a rule: no human adults were allowed to ride on her back outside of exceptional circumstances such as midgets and emergencies.
"Is it really so bad?" said Luna.
"Yes," said Celestia.
"I still hurt. Didn't you notice?" said Mag.
"I did indeed, but I am hardly going to ask why your thighs and backside so hurt, nor allow myself to wonder too much at it."
The sculptor eventually offered to carry Mag. To his credit, he wasn't sullen or ungracious about it. The idea of carrying a human around didn't seem to bother him; it was just the solution to a problem, and he didn't hold it against anybody, no matter how inconveniently small they were.
So Mag had ridden on his shoulder the whole way, in between his cavernous, hairy ear on her right and some kind of clockwork toucan on her left, which was apparently the thing that had been talking to him. It kept one round, black, glass eye on Mag at all times and clacked its beak at her whenever she moved too suddenly.
The walk had been disappointing. It was all empty corridors, and if there were any oil rats, Mag didn't see them. This meant she had nothing to distract her from the sculptor's aura, a musty miasma of bloodless reason, scholarship, and a joyless sort of creativity. He was the college professor whose class no one wanted to take, the kind who would happily teach a class of four people and fail all of them, who lived alone and worked alone and published books no one read.
She didn't mind his crotchety attitude, she shared his contempt for humanity, she liked his annoying bird that he'd apparently made, and she could forgive his "I know better than you about your own world" attitude. She couldn't forgive him for not being lonely. Even the eldest stank of loneliness. But as for the sculptor, what did he care that he was alone? He had a bird, a clockwork bird that did exactly what it was told and never argued back. A clockwork bird for a clockwork person.
The sculptor kneeled and Mag climbed carefully down his sleeve. She jumped off and he stood up again to his full height. Celestia alighted next to her and looked up at the shelves, and up and up.
"This is the magic section," said the sculptor.
"What are you going to do while we search, wait around?" said Mag.
"Yes."
What a shame, thought Mag, that I plan to take my sweet time. "Hey, Celestia, are we going to help you look?"
"I... am not sure. Do you feel that?"
"Feel what?"
"The ill will. The sense of menace. Mag, I appreciate your being here and helping like this, but I'm beginning to agree that these are the kinds of books no one should read."
"No such thing," said Mag.
"You clearly are not as widely read as we are."
Celestia bit her lip.
"Okay, but they're not evil. I promise you the worst books in this room are the kind you can't feel. Point taken, though. I'll hang back."
Celestia looked relieved. She gingerly pulled a vellum scroll off a rack, unfurled it, and started reading. Mag sat down on the floor and waited in silence.
Celestia rolled the scroll back up with distaste and put it back where she found it. She picked up another book bound in dense wood and iron hinges. She set it down next to her with an air of sadness after a few pages of reading and moved on to what looked like a 9th grade algebra book, the margins filled with someone's notes written in livid green ink, eventually slapping it shut and throwing it back to its proper place in revulsion.
The sculptor absentmindly pulled one of his cubes of brass out of a pocket. He pinched off a piece as if it were wet clay and rolled it into a ball between his fingers. He worked it with his yellowish, serrated fingernails - no, Mag realized, not serrated. The edges of his nails were shaped like various tools, rows and rows of them. Awls, knives, needles, saws. Nothing with multiple parts, but surely everything else imaginable.
He made a little flower, regarded it for a moment, squished it back into his brass cube, put it back into his pocket, and went back to waiting.
"Sculptor, do you have any books on human art?" said Mag.
"No, why would I?" said the sculptor.
"In that case, can I get a glass of water? I've got something you'll hate."
The sculptor made a tiny brass cup, pulled out a flask, dipped the cup into the water, and passed the cup of water down to Mag.
"Thanks, lord. Okay, see this glass of water?"
"No," said the sculptor.
"Fine, do you see this cup of water?"
"No."
Oh, right. "But I have a cup of water right now, right?"
He turned to his bird, turned back to Mag. "Yes."
Mag set down the cup of water. "Okay, well I just turned it into an oak tree."
He turned to his bird again, then turned back to Mag. "No, you didn't."
"Sure I did."
"You did not."
"Whatever point you are making, I already like this game," said Luna.
"Well, its roots and branches are pretty stubby - "
"It has neither roots nor branches."
"- it can't reproduce - "
"That's because it isn't an oak tree."
"- it's not made of wood - "
"That is not an oak tree. Is this another metaphor? I recall you telling me you would warn me the next time you used a metaphor."
Mag smiled. "It's not a metaphor. It's an oak tree."
Luna decided to chip in. "Do you mean this is a representation of an oak tree?"
"Nope, it's an oak tree."
Celestia looked up. "But you must admit it looks more like a cup of water than an oak tree."
"Yes, but it only looks like a cup of water, when in fact it's an oak tree."
"I want my cup of water back," said the sculptor.
Luna laughed. "What cup of water?"
"I want the object we are discussing back."
Mag drank the water and held it up. "Here you go. It's about a yard above the ground." The sculptor took it and smashed it back into his cube.
Mag clapped her hands together. "Right! For my next trick, I'd like a newly dead tiger shark and a tank of formaldehyde."
"What is a tiger shark?" said the sculptor coldly.
"It's a type of water dinosaur," said Mag.
"A dinosaur cannot be aquatic by definition. And no."
"A crucifix and a jar?"
"Enough."
Mag let it go. She'd had her fun.
"Where did you get all that?"
"A sculpture class."
***
"Maybe we should just go," said Mag.
Celestia tossed yet another book back to where she found it. "There must be something here."
"Must there?" said Luna.
"You still have that," said Mag, pointing at the wooden book, the only thing Celestia hadn't put back.
"I almost wish I didn't," said Celestia.
"Then put it back," said Luna.
"What is it?" said Mag.
A shadow stretched over them as the sculptor knelt. "Paravasi Mageia, by Ignatius VI," he rumbled.
"Yes?" said Luna.
Celestia picked it up and opened it to the title page. "'Transgression Magic; or, dark magic for persons of uncommon principle.'" She shut the book. "These are a collection of essays on some of the more unsavory subjects related to magic. Two or three of the essays looked potentially relevant to us, if uncomfortable to read. The rest of the book... well, I am not comfortable bringing this back to Earth. It has also been thoroughly saturated in the atmosphere of the works around it, some of which are so depraved that they seem to be leaking."
"I think I feel it now, that miasma you were talking about," said Mag. "If I left something here and let it soak for a few years, I don't think I'd want it back."
"Exactly," said Celestia.
"I'm bringing this back anyway, though," said Mag.
"Ugh. As you wish, but I should be the one to carry it. This isn't something to be touched with one's skin. Well, I suppose we're done."
"Then I will show you the way out," said the sculptor. He pulled out his cube one more time, and, with the sound of shrieking metal, he flattened into a rough dish. He set it on the floor, pulled out his flask, and poured water into it.
"You keep the exit in your pocket?" said Mag.
"The occasional uninvited guest is inevitable, but I can at least prevent them from leaving until they give an accounting of themselves," said the sculptor.
"I'll remember that," said Mag.
"Step closer to the water, if you please."
"Where is the edge?" said Celestia.
"Iskie," said Luna.
"A tricky one, but there shouldn't be a problem," said Celestia. Mag grabbed her tail. She didn't much like Underlake, and leaving immediately sounded wonderful.
"Sculptor," said Celestia, "I believe you overheard us talking before we entered. I'm sorry. I just want you to know that, while it's true we've never quite gotten along, I've also always respected what you do. Thank you for your time."
"If it helps, I've never liked you either," said the sculptor.
"Thanks for giving my species its book back," said Mag.
"After spending two hours watching you three circumvent my rules regarding the spread of dangerous knowledge, I would say you deserve nothing less," said the sculptor.
"May you always remain exactly as you are, lord sculptor," said Luna. "Universally disliked," she added privately to Mag.
They left.
***
Mag rolled over onto her back and saw the peryton. The peryton saw Celestia and bolted. Mag grinned.
"Sister, before anything else, there is something we must discuss," said Luna.
"Yes?"
"The Nightmare is back."
"What?!" Celestia rushed forward to look closely at Mag, just like her sister had. "Are you two all right?"
"We're fine," said Mag.
"It made an offer to Mag, Mag cast her out, and the Nightmare left peacefully," said Luna.
"But where is it now?"
"Earth," said Luna.
"It said something about Eastern Europe," said Mag. "I'll show the place to you on a map later."
Celestia began to pace. "But of course it could be anywhere tomorrow, and somewhere else again the next day. We must find its host and keep them contained, or else who knows what could happen?"
Mag sat up and raised her hand. "Hey, I've been thinking. I don't know if the Nightmare can affect our world the same way it affected yours. The only host it could possibly take that'd be as bad as Luna would be the eldest, and I don't see him going for that kind of deal. I'm going to guess we get some kind of magical tyrant that needs to be put down, and a tyrant with powers doesn't sound so different from one with nukes. Scary, but it's not like we don't have those anyway."
"I brought it here, and that makes it my responsibility," said Luna. "And doubly glad would I be to do it if the task involved pulling down a tyrant. There is nothing I loathe so much as tyranny."
"I also have to wonder what the consequences would be for one of your already politically powerful tyrants to gain the power of the Nightmare," said Celestia.
"Fair enough," said Mag.
"Let's finish this discussion at your home," said Celestia. She teleported them to the mirror.
Mag stumbled. She would have appreciated a warning.
"I'm sorry," said Celestia.
"It's fine. Hey, I feel like I'm forgetting something important," said Mag.
"Oh! The book!" said Celestia. She poofed away, then poofed back with the book.
"Yeah, that must be it," said Mag.
"I have the same feeling, and it hasn't gone away."
"Huh," said Mag. "Another thing to work out at home. God, I would kick orphaned puppies for a cigarette right now. That and a real breakfast. I'm thinking fried mushrooms and scrambled eggs. Can you guys eat eggs?"
"Yes, and that sounds delightful," said Celestia.
Mag took Celestia's tail in hand again. They passed through the mirror...
... and burst out of the California lake together. Dawn had come and the sun was behind the treetops. Celestia broke through the ice on the surface of the lake by flinging her wings open; water and shards of ice sprayed to either side of her. She shook out her mane like a model in a shampoo commercial. Mag lurched out of the lake on all fours.
Mag looked up to see something of a tableau. The shore was absolutely crowded with people. Most of them were EMTs in wading boots and warm clothes. A coroner stood by, leaning against a tree and shivering. John Hardly sat on a nearby gurney, wearing two trauma blankets and looking teary. There was even a small news crew with a handheld camera, though no one had a microphone. The camera's red light was on.
There were ten humans onshore, not counting Mag herself, and all of them were staring at Celestia.
Mag stood up straight. "John Hardly, get over here so I can kick your ass."