“I’m sorry sir. That volume is missing too.”

They stood together in front of the circulation desk, with a stack of white cards in front of them. Every recent map catalog that might be able to give them a heading to the hippogriff homeland.

The librarian was yet another creature that Theo could scarcely imagine existing, a being of strange transparent crystal with faintly glowing eyes. Granted, she could only see through the pony when the sun caught her just right, but… she wasn’t so sure she wanted to be up so close to them. It was easier when they were passing in the city far away.

If she needed a reminder that she wasn’t on Earth anymore, this was it. I probably shouldn’t worry about figuring this out too hard. I’ll lose my mind.

They had been in the library for hours now, while Sharp searched through the various navigational and informative sections. But after hours of finding nothing, they’d finally gone to the librarians for help. “You’re telling me every chart newer than five years is… either checked out or not available?”

The librarian nodded again. “I already explained it, sir. But we only have two copies. One is on loan to the palace, and the other wasn’t returned… several months ago.” She looked up from the thick stack of files in front of her, clucking her tongue once in disappointment. “Somepony is going to have a serious fee waiting for them when they get back.”

“And…” He shuffled through his stack of white cards, settling on three more. “What about these?” They were the books that should’ve talked about hippogriffs, discussing the developments in the south and the appearance of this new race in Equestria.

She shook her head again. “I wish I could be more helpful to you all, but… several of those aren’t on the shelves where they should be. And a few are…”

“Checked out to the palace,” Sharp said, his tone grim. “Fantastic, great. Do you know if there’s anywhere else in the Empire that would sell navigational charts, if we can’t copy them here?”

She shook her head. “I’m afraid not. The Empire is the end of the line for shipping. I don’t know the details, but… you should try Canterlot. It’s the hub for all Equestria’s air traffic. They’re bound to have the charts you’re looking for. The Royal Library has a collection a hundred times the size of what we do.”

“It’s okay,” Theo said, tugging weakly on his foreleg. “We tried, Sharp. They’re obviously doing their best.”

He grumbled for a few seconds more, then finally let go and turned away. They walked back out the front door, leaving the sprawling library empty-handed.

“It’s absurd that they wouldn’t have charts to one of the newest, most interesting places in the world,” he muttered, dragging his hooves a little as they left. “It’s as though ponies just don’t care. They just sit by, content to stay ignorant forever. Most of them don’t even know how many times we’ve been in danger in the last few decades. They don’t know who the Elements of Harmony are, they don’t know how each of the princesses rose to power…” He stopped, glaring back at the library. “They should’ve had a dozen times that many books.”

“It did seem weird that it was only the books about hippogriffs that were missing,” Emerald said. “There were so many books on those shelves, but only a few weren’t where they should be.”

“Like someone took them out on purpose,” Theo whispered. She wasn’t even sure where the thought had come from. But now she considered it, she couldn’t get the idea out of her head. Someone didn’t want ponies to know about hippogriffs. Why, though? She didn’t have the information for that yet.

“Well, she was right about one thing. The Royal Library will have everything we need. They’re very serious about those who try to steal. There was a time you could go to prison for taking a book out of there. We’ll just… get into the air. I can get us down to Canterlot easy enough. It’s… just a minor detour, really. We’re still on track.”

Without the hours of research they’d expected to spend in the library, they had a little more time to be tourists in the city. They visited the Crystal Palace, stopping long enough for Theo and Emerald to gawk themselves silly at the incredible structure. They ordered street food, haggled for airship supplies, and were back at the inn by nightfall.

Theo slowed to a stop outside the Feather store, staring through the glass at the constant electric light within. Sharp stopped beside her, following her gaze. “Their gadgets are overpriced,” he said. “Don’t waste your bits. If you… had them to waste. Which you don’t. We can’t afford it.”

“It’s not that.” She lowered her voice to a whisper. “This… this probably sounds crazy, but looking in that place reminds me of somewhere from home. Those gadgets, the way the store is laid out… it’s familiar.” She looked up, meeting his eyes. “You’ve been watching the Bridge for over a year, right? Have others like me ever come through it?”

To her surprise, Sharp looked away awkwardly, heading into the inn ahead of her. “No creature like you,” he said. “Never. You’re the first.” He remained reticent about the subject all night. Theo didn’t press, though she wanted to. I wonder how easy it would be to take one of those things apart. Is someone selling their e-waste to Equestria somehow?

The next morning began with bland oatmeal, and a trip through the icy streets of the outer city to the drydock. Sharp paid, and soon enough they were back aboard the Horizon, with the signs of new maintenance all over. There were fresh sandbags, the gasbag seemed packed almost to bursting, and some of the machinery had been serviced.

“Just a minor setback,” Sharp said, as he took the helm. Theo tossed the mooring ropes free, and they began to rise rapidly up. The spectacular city of crystals soared up around them, then fell away to the size of a toy over the next several minutes. “Just wait until you see Canterlot,” he said, a grin finally returning to his lips. “The Crystal Empire might seem more magical, but… Canterlot is more alive. It’s basically the center of the world. If we’re lucky, we might even be able to see Celestia raise the sun.”

“Which means…” Theo tightened the vest a little about her chest, but it was doing its job. Whatever strange wool the ponies made their clothes out of, they were warm enough that she didn’t freeze up here in the thin air. Granted, the wind blowing past them was enough to force them to raise their voices, even more so once the engines below started to rumble. “Raise the sun? Some kind of… Mass?”

They didn’t seem to understand that. Sharp looked to Emerald, and Theo couldn’t quite read the expression. Like they thought she was crazy. “Who raises the sun in your world?” Emerald asked. “Some… Traveler princess, I bet. Probably just a different name.”

Out over the edge, their airship was humming along now, leaving only a faint trail of exhaust. The engines burned something, though whatever it was didn’t leave much smoke in its wake.

“I don’t…” She hesitated. “What does ‘raising’ the sun mean, exactly?”

It was Sharp who answered this time, after several pensive seconds. “A long time ago, there was a court of the most powerful unicorns in the world who worked together to lift the sun into the sky in the morning, keep it on its path during the day, and replace it with the moon at night. But the skill was difficult, and their numbers were always dwindling—they lived such difficult lives that they usually died young. Then Celestia and her sister came around. No two stories about where are quite alike—but they took over the job. Now they keep the days and nights working right in the whole world. Every creature in every nation benefits, even those who live on the other side of the planet from us.”

“That’s… not possible,” she muttered, eyes wide. But even as she said it, the words seemed hollow. Not possible like a horse flying. Not possible like a magical doorway in the sky, that made her a girl and covered her in feathers. Not possible like a person made out of rock, or a magical heart that floated in the air and kept the city from freezing. Little of what she’d seen in the last week was possible, but it had still happened.

“I wanna see the princess too!” Emerald called, bouncing eagerly between her hooves. She hadn’t returned completely to her energetic self—whenever they stayed in one place for too long, her mood would rapidly darken. But so long as they stayed moving, she seemed to be doing well. “Just wait until you see it, Summer! It will make much more sense then.”

“We’ll try to stay for a morning ceremony,” Sharp promised. “We can talk about the scientific side after you’ve been there. I would be curious to hear how your world works. I’m guessing you don’t have a sun princess?”

She nodded her agreement, walking past the helm to lean off the front of the ship. She couldn’t get an unobstructed view above them with the gasbag, but below—she could almost recognize that wilderness. It looked like Canada’s highlands, the same country she’d flown over during her initial trip to Barrow. Only this time it looked even more untamed, more remote. There was no occasional village or distant road to break up the trees and tundra.

“No one does anything to ‘raise’ our sun. It’s just… the natural laws of the universe. Our sun has more mass than our planet, so our planet orbits.” And I bet you this place is exactly the same. You’re probably Egyptians or something without even knowing it. Sun worship.

But she didn’t want to argue. Sharp asked her a few more questions about Earth, and she explained with a brief recitation of Newton’s laws, and some not-to-scale sketches of their solar system. Primary school stuff, with as much of the underlying math as she remembered.

They flew for a few days, running the engines at low power and occasionally altering course to avoid a storm. As they flew, the snowy wastelands below gradually greened, with less and less white outside the peaks of the tallest mountains.

To her surprise and embarrassment, Sharp gave up his bedroom for the two of them, taking a cot of his own down to engineering where he could sleep beside his engines. How he could get any sleep with the constant droning, or the gigantic opening to the sky right beside him, she didn’t know. But she didn’t argue.

It was on their third day that they finally struck a patch of completely still air, over an evergreen forest broken with a stream and distant lake. Theo had been tinkering with a bit of wire and tools Sharp loaned her, and she nearly cut straight through what she was working on as the Horizon came to a sudden, abrupt halt.

Emerald’s head emerged from the stairs a moment later, peeking down from above. “Guess where we are, Summer.”

She glanced to the porthole, and could see only the pristine wilderness. No sign of civilization outside, certainly no city at the center of the world. “I have no idea.”

“The perfect place!” she answered, yanking on one of Theo’s legs.

She squeaked in surprise, then set her work down and let the child tow her towards the stairs. “Perfect for what?”

“To teach you how to fly, obviously!” she called, beaming. “Or at least how to glide. A bird on an airship who can’t even use her wings… that’s crazy. If I can learn up in Sleighsburg, you can learn here.”

They stepped out onto the deck. She turned to the helm, where Sharp was shutting down the engines. “Don’t look at me,” he said. “Her idea.”

“I’m not sure…” They stopped at the railing. Theo took one glance over the edge, then yanked herself back firmly enough to break free of the little pegasus. “No bucking way.”

The translated profanity made Emerald’s expression wilt a little, but then she took off. “Wait, we’re not going straight down first. I’m gonna go grab some clouds. Be right back!” And she took off, streaking towards a path of thick white in the near distance.

“You could’ve told her no,” Theo said weakly. “I’m afraid of heights.”

“More reason not to stop her,” Sharp said, crossing the distance between them and glancing over the edge. “If I can jump with a parachute, you can jump with wings. It’s not as scary as it looks.”

“You’re right,” she agreed. “It’s much worse.”