“This will be the most awesome book signing event ever!”

A. K. Yearling rolled her eyes at the hovering pegasus, who was hanging a banner from the crystalline ceiling. “It’ll certainly be the first book signing event I’ve ever done in Ponyville.”

“What better place to hold one than inside a library?” Twilight set down the table on the spot within her castle library where Yearling would greet her fans and sign books. She’d spent most of that morning determining the optimal location.

“Oh, I don’t know. A bookstore, maybe? So, you know, ponies could buy a copy that I would then sign?”

Rainbow Dash waved that away. “Sure, that’s how it’s usually done, but this is a princess’ castle we’re talking about!”

Yearling sighed. “I think you’re missing the point.”

Twilight placed a quill and ink pot on the table. “Barnyard Bargains has stacks of Daring Do and the Calamitous Catacombs available for purchase. The flyers announcing this event make that very clear.”

“I know, I know… and my publisher did go along with this.” She trotted over to the table. “Hard to turn down a royal invitation.”

“All the trains from Canterlot for the next few hours are sold out,” Twilight pointed out. “Plenty of books will be sold. Filthy Rich has even set up a kiosk at the train station.”

“I’m here, so there’s really no need for the sales pitch.” Yearling sat down on the plush cushion behind the table and went through the motions of signing a book with an un-inked quill in her mouth. “This works.”

Rainbow Dash put on the table a cup and a pitcher of water.

Yearling got up. “Look, this isn’t the only reason I agreed to this event.”

Dash tilted her head. “What’s that supposed to mean?”

The disguised pegasus went around the table to where Twilight was standing. “Could you cast a privacy spell?”

Twilight looked around. Nopony else was present, but somepony could always walk in. Must be Daring Do related, she thought.

The other pegasus suddenly dropped to the floor next to them. There was no objection from Yearling, so Twilight went ahead and cast her spell. A translucent lavender shell surrounded them.

“Does Ahuizotl have a new relic that threatens Equestria?”

“No, Dash, that isn’t what this is about.”

“Dr. Caballeron?”

“No, this has nothing to do with my next book.”

Twilight took a step in front of Dash. “Then what is this about?”

Yearling adjusted her cloche hat. “You understand that what I’m about to tell you must be kept in the strictest confidentiality. To be honest, I’d rather not tell you at all.”

“You can trust us, of course.”

“Absolutely!”

Yearling searched their eyes for a few seconds before settling on Twilight’s. “In the Everfree Forest, you encountered Lyra Heartstrings with a changeling.”

“Wait. What?”

Twilight gave Rainbow Dash an apologetic look. “Yes, Dash, I did.”

“And you didn’t mention it?!”

“Lyra insisted the changeling wasn’t a threat.” Lyra and the changeling had also promised proof of that, which she had yet to receive. Only the fact that the changeling had not been seen again… Her eyes turned to Yearling. “How do you know about this?”

Yearling dropped to her haunches. “I’m vouching for that changeling. Everything they told you is true. It is not a threat.”

Rainbow Dash also dropped to her haunches. “Uh… what is true? I wasn’t there.”

“Basically that the changeling wasn’t part of Chrysalis’ hive,” Twilight said, “and was no threat to anypony.”

“There are other hives?”

Yearling stood back up. “Yes, Dash, there are other hives. There are also drones who do not belong to any hive—precious few, but they do exist. I’ve… encountered a few in my travels.”

Twilight let that soak in. Ponies knew so little about changelings, and what was known centered on Chrysalis. Were other hives like hers? And what about these… what to even call them? Were they drones if they had no queen? Daring knew them well enough to vouch for them?

And then there was Lyra.

“Why would Lyra be with one of these changelings in the Everfree?”

Yearling sighed. “Yeah, talk about bad luck. What were the odds of you stumbling upon them like that?”

Something Twilight had wondered herself. That it had been part of a time loop, that the time loop wouldn’t happen until they were in a position to see the changeling… that could not have been a coincidence. “That doesn’t answer the question.”

“No, it doesn’t.” She removed her cloche hat, this time revealing only a mane. “Lyra was keeping an eye on Smooze for me. Last I’ve heard, you’re making good progress with that voice synthesizer.”

Well. That explained a few things. Clearly, that changeling was the go-between.

Dash glared at her. “We would’ve kept you informed ourselves, you know, if you’d only asked us.”

“Old habits die hard?”

Twilight had never seen the explorer so… fragile? “No real harm done, I suppose.”

Yearling gazed at the lavender hemisphere still surrounding them. “I’ve said what I needed to say. You can drop that now.”

Meg’s predicament came to mind. The privacy shield remained. “There’s something I want to ask first.”

The cloche hat returned to Yearling’s head. “Go ahead.”

“Would one of these changelings be willing to assist us? We could use a shape-shifter.”

Dash jaw dropped. “We can?”

Twilight ignored her, keeping her focus on the disguised Daring Do.

“What would be in it for them?”

“What would they want?”

A smile grew on Yearling’s muzzle. “Could you be more specific about what task you had in mind?”

“Fair enough.” Twilight had the distinct impression that the adventurer and businessmare was far more experienced at negotiating than herself. “I need a changeling to take on Meg’s pegasus form while Meg herself is nearby in her human form. This is to happen when Tirek is released from Tartarus. The human media will be present; the deception is for their benefit and Tirek’s.”

Yearling’s jaw dropped.

Dash nodded. “Yeah, that makes sense.”

“None of that makes sense to me, starting with ‘Tirek is released from Tartarus.’”

The explorer had kept their secrets so far. “What I am about to tell you is a royal secret.”

That elicited a sigh. “What’s one more secret?”

A red-hot crystal sphere, a few inches in diameter with a pair of metallic poles at opposite ends, floated in Moondancer’s magic as they waited for it to cool down. The experiments had been terminating in runaway exothermic reactions, and no one and nopony had figured out why as of yet.

“Still no electricity generation,” Sunset Shimmer said, after checking a meter.

Meg sat in front of a computer workstation, idly fingering the enchanted gem of her new pendant—but careful not to squeeze it. “Still no idea what the simulations are missing?”

“It’d be nice to know what, exactly, is generating that heat.” Jerry checked the recorded data on his computer. “No detectable radiation, not that that means much in this place.” Inside that crystal was highly radioactive waste, fuel for the integrated magic generator.

“All that means is that the magic generated from the magically accelerated atomic decay is being efficiently converted to heat instead of electricity,” Martin said. “Where else would the energy be coming from?”

Not that conservation of energy applied in this place, as everyone knew, but they had already reproduced the symptoms in the testing vault back on Earth—behind substantial lead shielding, of course, though unnecessary as it turned out—so that ruled that out.

Diana walked over to the levitated sphere, no longer radiating heat due to Sunset’s cooling spell. “It’d sure help if we knew what the heck was happening in there. We might not have a choice but to send a sample off for isotope analysis.”

Everyone looked towards the unicorns.

Sunset looked apologetic. “Still working on that spell.”

The best magic could do was to exhaustively iterate over all the possible isotopes, pulling them out one by one. Besides the fact that no unicorn could cast that spell that many times in a row, many of the extracted elements would not play nice with an oxygen-containing atmosphere—nor with nearby biological organisms. The problem was that sending the sample off to a human lab for analysis would take a lot of time.

Moondancer came to a decision. “We need to eliminate variables. Start with a pure isotope, one which decays in one step to a stable isotope. Analysis becomes trivial with our existing isotope extraction spell.”

“We’re not going to find enough of a suitable isotope in that waste,” Jerry said. “The predominant heavy elements have complicated decay chains.”

Diana returned to her seat. “Does it really matter? Generating magic from atomic decay isn’t the problem. Magic generators prove that. It’s converting that magical energy into electricity that’s the problem.”

It was a discussion to which Meg had nothing to contribute; she was neither a physicist nor a mage. She decided to stretch her legs and walk about the converted cavern.

Flash.

Meg turned around. Twilight was there.

“Sorry to interrupt, everypony, but I need to borrow Meg for a bit.”

“For how long?” Meg asked, fingering her pendant, an act which did not go unnoticed by the alicorn.

“I’m… not sure. Not too long, I hope.”

“Well…” She looked back at the others. “It’s not like I’m all that much use here right now.”

“We’ll let you know what we’ve decided when you come back,” Sunset said.

“If we can decide,” Jerry muttered.

Meg went back to her workstation to retrieve her purse. Upon returning to Twilight, she shrugged her shoulders. At least she’d be doing something useful. “Let’s go, then?”

One teleport later and she found herself just inside the main mine entrance, her eyes momentarily blinded by the sunlight pouring in. Shielding her eyes with a hand, she noticed another pony present in the tunnel, a pony wearing a pith helmet.

Daring Do looked up at Meg with a critical eye. “You know she’ll need to be a pegasus,” she said.

Twilight smirked. “Just watch.”

We’re flying somewhere? Meg got her phone out of her purse and held it out to Twilight, who took hold of it with her magic. That having been taken care of, her hand returned to the pendant. It was that enchanted gem that had prevented her transformation when she was brought to the cavern along with the others. But that wasn’t its only function.

She gave the pendant a squeeze, and she no longer towered over the other ponies.

“Impressive,” Daring said.

Twilight returned the phone to its holder around Meg’s front leg; her purse had vanished along with her clothes, to return when she changed back to a human. “As you know, Discord cast a standing spell that transforms an individual between pony and human upon an inter-realm teleport to and from the human realm. I reversed engineered the mechanisms and that pendant is the result.”

Daring politely nodded. “I can see how that’d be useful.”

Naturally, Twilight wasn’t going to leave it at that. “By wearing that pendant, the trigger for the transformation is blocked. Meg can arrive here with other humans, none becoming the wiser as to her dual nature. By squeezing it, it tricks Discord’s spell into thinking she’s about to leave or has just arrived in this realm, thus triggering the appropriate transformation.”

“My curiosity has been satisfied,” Daring said, preempting the remainder of the lecture.

Twilight sheepishly smiled. She unfolded her wings and began to hover. “Give me a call when you’re ready to return to the office.”

The alicorn flew away.

Meg still had no idea what this was all about, but it evidently didn’t involve Twilight. “Are we flying somewhere?” she asked. Why else would she need to be a pegasus?

“You could say that.”

“Because?”

The explorer was enjoying this too much. “Because I also have a solution to a problem of yours.”

Meg gave her an annoyed look, which did nothing to prompt an explanation from the pegasus. Only the fact that Twilight had vouched for… whatever this was prevented her from going back to the cavern office the hard way. “Fine,” she said, unfurling her wings. “I’ll follow you.”

The mine reached the surface on the opposite side of the mountain from Canterlot. Ruins of defunct ore processing facilities littered the mountain side. Nopony was around to see them fly away, gaining altitude as they headed east.

For several minutes they flew, until they reached a forested valley on the other side of the next ridge of mountains. Daring descended. There didn’t seem to be anything terribly ominous about those trees. Meg didn’t think this valley was still part of the Everfree Forest to the south, but unfortunately she couldn’t use the map app on her phone to tell her whether it was.

At least it wasn’t some hot and humid jungle.

Daring seemed to be aiming for something, but what Meg couldn’t tell. It was just a bunch of trees nestled in the valley between the mountains. No stone temple, no obelisk, no sign of any kind of civilization, recent or ancient.

Twilight did know what this was about, right?

She knew the way back to Canterlot and that mine—and so long as she did, she’d follow. It was flying exercise, if nothing else. Rainbow Dash still got on her case about that.

The two pegasi slowed down as they neared the canopy. Through the branches they threaded until only trunks surrounded them. Dappled sunlight danced on the plants covering the forest floor. Over there the vegetation was sparse.

That’s where they landed. Meg’s ears darted about. Leaves rustled in the breeze. Birds sung in the distance. An insect buzzed by. Not the Everfree, it was safe to say.

Daring gave her a smirk.

“Well?” Meg asked.

“Be patient.”

Whatever the hell that was supposed to mean.

Meg jumped back. Something had rubbed against her leg. It was a cat. A white and fluffy, perfectly ordinary house cat.

A cat that had no more business being here in the wilderness than she did.

Rustling sounds came from all directions; this time the breeze had nothing to do with it. Meg spun around. From the surrounding bushes emerged a black panther, a lynx, a tiger, and a cheetah. The only way out was up, but they were already too close and poised to leap; she wasn’t Rainbow Dash.

Daring Do casually looked around, her wings folded.

Her nonchalance was irritating. Maybe it’s just another Tuesday for you…

The big cats held their ground—waiting for something? The house cat was rubbing against her legs again, serenading her with cute meows.

There was something oddly familiar about it.

Meg angrily turned to Daring. “You didn’t.”

“Ah, but she did!”

Meg spun towards the deep, masculine, gloating voice. A collection of mismatched parts came into view: dog-like hind limbs, ape-like forelimbs, an elongated dog-like head with eyes positioned over his nose at the end of the snout, a long monkey-like tail with—and most absurdly of all—a hand on its end. At least the creature was bilaterally symmetrical, unlike a certain draconequus.

This has to be a nightmare. She must’ve dozed off. Princess Luna would come by any moment to put an end to it—except for the tiny detail that she was already lucid, she could clearly remember the events of the last few hours that led up to this, and the princess was nowhere in sight. Face it: it’s happening.

“Why?!” she demanded of Daring Do.

The explorer shrugged. “I had an offer too good to pass up.”

Ahuizotl laughed maniacally, exposing his sharp canines. “And how fortunate for you that she took it.” He took hold of the house cat and began to pet it. “Daring Do has told me all about you and the world you come from. You need a solution to a certain problem, and I want access to your world.” He menacingly leaned forward, his necklace swinging. “Let’s make a deal.”

Twilight knew about this? That was inconceivable. Daring must have lied to her. There was no other possible explanation.

The pegasus in question whispered into her ear. “Here’s your chance to ask what’s his deal with my books. Quick, before he monologues.”

Meg scowled at her. This wasn’t some joke. How could she—

Wait. That conversation back in Las Pegasus—the way Daring had reacted to her questions—she had proposed the very situation she now found herself in. Meg took another look at the felines surrounding her. Something wasn’t right. Solitary predators shouldn’t be behaving like this, like… henchmen. It was all so… cartoonish. MLP might have been a cartoon, but the physical Equestria she was in… not so much.

Her eyes returned to Ahuizotl. She had no idea what he was, but in the real world there was no such thing as a species with only a single instance—draconequus excluded. “Where’s the rest of your kind?”

“What do you mean?” he defensively asked.

“You know: your parents, siblings, distant relatives… other whatever you are. You must come from somewhere.”

“That’s none of your business,” he said a little too hastily.

Meg locked her eyes onto him. She might not be the Element of Honesty, but it was obvious enough that something fishy was going on. “I’m making it my business. Answer my question, or I won’t answer yours.”

Ahuizotl nervously licked his lips, his pleading eyes fixed on Daring Do.

The pegasus shook her head. “Okay, you got us. None of my books ever had a reason to go into that backstory.”

Meg stared blankly at her. “What?”

“Drop character, everypony.”

All around them, green flame swept over Ahuizotl and the felines, the house cat included.

Six changelings surrounded them.

“What?”

“None of my archvillains are real,” Daring explained. “It’s all playacting, brainstorming for my next book. That’s what Twilight and the others party-crashed in that episode.” She shrugged. “We went with it, didn’t break character; it was the lesser of two evils. Sorry about the charade. I couldn’t resist. I dunno, maybe Rainbow Dash is rubbing off on me.”

Meg unfurled her wings in anger. “I got pulled out of work for a stupid prank!”

She tried to take off, but a changeling telekinetically kept her on the ground. “Let me go!” She was so going to have words with Twilight over this. She already had enough crap in her life.

Daring Do sighed and removed her helmet. “It’s not just a prank, I promise, okay? Don’t go. It’s important.”

Had she ever seen her without a hat or helmet before? Was it truly important? Would Twilight have fetched her if it wasn’t? That pony wasn’t into pranks, after all.

Meg’s wings re-furled, and the changeling released its telekinetic grip. However, she wasn’t quite done with this prank yet. She considered the implications of what she’d just seen. If what the Mane Six had stumbled onto was just brainstorming… “That relic… the one that’d do something to the sun for a few centuries… not real?”

“Nope,” Daring said, shaking her head. “And that whole temple was a set.”

Meg stared at her.

“We, uh, find that a convincing set helps with the ideas, makes for a more convincing predicament. Hey, don’t judge me; I can afford it now.”

She still wasn’t sure she believed her ears. “I thought all your books were based on real-life experiences.”

“For some definition of ‘real.’ I had to tell Twilight, and especially Rainbow Dash, something.” She rolled her eyes. “Believe me, I paid a price for that. The lectures I got about informing the proper authorities whenever I stumble across dangerous magical relics…”

Great. So the Mane Six stumbled onto a larping session. And she managed to convince them to keep it secret.

“But Twilight knows the truth now?”

Daring tilted her head back and forth. “Sorta. She knows about the hive-less changelings, but not about the service they provide me—and I’d like to keep it that way, if you know what I mean—apart from being a messenger between myself and Lyra. That, uh, incident kinda forced the matter.”

Meg stared at the—hive-less?—changelings. “So which of you was the one I saw with Lyra?”

The one in the middle raised a hesitant hoof.

She turned back to Daring. “What’s the point of this, if not just a prank? What does Twilight think is happening here?”

The pegasus shook her mane and returned the pith helmet to its proper place. “Look, I really did get an offer too good to pass up. It came from Twilight. These changelings can solve a problem of yours.”

Daring nodded at one of them. A flash of green fire, and it took on Meg’s form. It was like looking in a mirror; even the phone and its holder were copied. But it couldn’t be functional, right?

“Okay…”

Daring walked over and stood next to faux Meg. “Now imagine that you, as a human, are standing next to this ‘pegasus’ in front of cameras as Tirek is released from Tartarus.”

Meg was speechless. It was so simple, and it solved both problems: Tirek would have no reason to think Meg the human was also Common Ground the pegasus, and any human who tried to out her dual nature would be made to look like a fool.

There were details, of course; there were always details. This changeling would have to convince Tirek that it was, in fact, Common Ground—but that was a problem she herself had. After all, all of Tirek’s shared past with her was still in her future. How much had Twilight told them about the alleged time loop? And she’d have to be there when Tirek was released; furthermore, why would the cameras pay attention to her? She could worry about those questions later; it was safe to assume those details were already on Twilight’s checklist.

But is it worth putting myself on national television for it?

A different thought came to her…

No, don’t get ahead of yourself. There were too many questions, like how did Tartarus affect changeling magic? Maybe it couldn’t set foot beyond those gates without blowing its cover. And don’t even think of having it take my place as a kidnapping victim on magic-less Earth.

Daring was smirking at her. She really was enjoying this too much.

“Yes, I’m interested,” Meg said, before glaring at her doppelgänger. “You are to keep away from my husband, got it?”

“I’m back,” Meg said, as Twilight teleported away. She walked over to her workstation. “What did I miss?”

The spherical crystal with the metal poles rested on a table, this time with wires connected to the poles. Those wires led to a box, to which a large fan was plugged in. The fan was spinning full blast.

“We figured it out,” Moondancer said. “Electricity was being generated, but not at the poles. The current was heating the nuclear material inside the sphere.”

“Ironically,” Sunset Shimmer added, “the integrity spells we cast on the quartz, which may have prevented it from exploding if any of that material had vaporized, was part of the problem. It also accidentally prevented electricity from being generated outside the sphere and inside the poles.”

“So the computer models were correct after all,” Diana said. “What about you? You were gone for over an hour.”

Meg put down her purse. “Oh, nothing much,” she said. “Me and Daring Do had a face-off with Ahuizotl. Did you know he knows about humans? I think he wants to plunder us or something.”

“But you defeated him, right?” Sunset asked, feigning boredom.

“Oh, yeah, totally defeated him. All I had to do was ask him where the others of his kind were. Totally stumped him. He’s overrated, if you ask me.”

Jerry facepalmed. “If we don’t have a need-to-know, you could just say so, you know.”