Princess Celestia’s mind was a thing of wonder. Centuries of political brokering, cultural shaping, and applied celestial mechanics had made her capable of incredible feats of parallel processing, forward planning, and complex cogitation.

And yet, when a pair of guards opened the doors to her throne room, that incredible mind still experienced an all too equine moment of pure shock.

“Princess!” Twilight Sparkle cried from her spot in the throne’s fountain. She stopped trying to wrestle her baby dragon out of it and bowed as best she could while keeping her muzzle above the water line. “I’m so sorry! I don’t know if Spike was thirsty or bored or what, but he jumped off of my back and ran into the fountain and started splashing and I couldn’t get a grip on him with my magic so I had to go in because the guards were just smiling and—“

A princess-sized hug cut off her rant. “It’s alright, Twilight.” Celestia lifted both out of the water and dried them with a soft touch of solar heat.

The filly bit her lip. Floating in her mentor’s magic clearly wasn’t helping her calm down. “It is?”

Celestia set both down. “It is.” She looked about the room. “Though I would like to know why nopony helped my personal student when she asked.”

The visible guards stiffened more than usual, their eyes snapping forward. The hidden ones made every attempt to be absent without actually moving.

“A matter to discuss later, then.” Celestia turned back to Twilight and sat before her. “You have nothing to worry about, Twilight. Though you may want to keep Spike at home for a few years.” She winked.

Twilight nodded fast enough to send her mane flying. Celestia couldn’t help but smile wider as she began the day’s lesson. The faint glow about Twilight and Spike, one only she could see, didn’t concern her. Both had only swallowed a few drops’ worth of water from the Fountain of Youth, and it wasn’t as though it had a lasting effect on mortals.

A week later, Celestia entered her throne room again. Spike was absent, which she’d expected. Twilight was present, likewise expected. The glow from the Fountain still clung to the filly’s aura, which was unexpected. but not concerning. The Fountain’s magic clung to the especially magically potent. It took a good three weeks for Starswirl’s sample to start diminishing back when they had first discovered the magic spring.

Celestia was sure it was nothing to worry about.

A month later, she wasn’t. The glow was still there. Indeed, it had slightly but noticeably increased.

“Princess? Is something wrong?”

Twilight’s question snapped Celestia out of her shock. She put on a carefully crafted smile, maternal warmth laced with just the right amount of embarrassment. “I’m terribly sorry, Twilight. It’s been a very busy week and one of us forgot to take notes last time. Where did we leave off?”

Celestia knew precisely where they’d ended the lesson last time, but the ensuing lecture gave her plenty of time to dedicate a mental track to addressing this new problem. The only way the glow could intensify was if Twilight was a nascent alicorn. Had she drunk enough from the Fountain, she’d have ascended there and then. Even now, her magic was interacting with the trace amount she’d ingested in a feedback loop that would inevitably give her wings.

Well, thought that portion of Celestia’s awareness, at least she’s given me more warning than Cadence ever did.

The two sisters stood side by side in the throne room, their eyes looking at a stained glass window while their minds were too busy thinking to register it. A small part of Celestia that had nothing to do with mental partitioning still couldn’t believe that Luna had returned, whole and sane. The rest, having finally divulged the full details of the Twilight situation, just dreaded hearing what Luna would have to say on the matter.

Luna remained silent for most of a minute before she let Celestia find out. “The plan as you have described it relies entirely on hope, luck, and an insane amount of faith in ponykind’s better nature.”

Celestia held back a wince. “It was the best idea I could think of.”

“I am aware.” Celestia saw Luna’s smirk out of the corner of her eye. “I just described every plan you’ve ever made when given less than a generation to prepare. Indeed, much as our ponies are foaling later in life, your improvisational skills seem to have worsened.”

A hateful little bit of Celestia spoke as it had for more than a millennium, reminding her how Luna’s return would entail more than just a happy reunion and hoofing off the night shift. She quashed it with long practice and said, “I don’t suppose you have any better ideas?” The bite in her voice suggested the practice hadn’t been long enough.

Luna shook her head. “Several, but none that would work this far in the process. Most would not have worked by the time you had realized there was a problem. The most harmless I would have used as a preventative measure.”

“Nothing at all?”

“Well, I could try going mad with jealousy and instigating a coup, but we know how well that went last time.” Luna took in Celestia’s shock for a moment before adding, “That was a jest.”

“I know.” Celestia hadn’t. She’d hoped, but she hadn’t known, and that fact that she hadn’t tore at her. “I… just wasn’t expecting you to joke about that. Not so soon after.”

Luna shrugged her wings. “I have many ways of coping with that foolish act. But let us return to Twilight Sparkle, your plans for her, and the countless things that could upset them.”

“Luna.”

Luna held up a hoof. “Peace, sister. If I speak harshly, it is only out of concern for Twilight. The mare who freed me from my Nightmare was certainly not ready for ascension. She was scarcely more so at Mi Amore’s wedding. I fear we shall both lose a friend after knowing her for far too short a time, be it to madness, resentment, or both. Madness especially comes to mind, given how freeing Discord is but one step in this grand scheme.”

“It presents a chance to make him an ally.”

“It also presents a chance to let chaos consume the world until time has no meaning.”

“Yes, but—“

Luna stuck Celestia with a hard glare. “Do you recall in what year we defeated Discord?”

Celestia felt her ears flatten. She looked away. “… Q over salmon.”

“Q over salmon. I would not see what comes after that. Why not simply give the Bearers the Elements to keep close in case of emergency? After all, they might have been able to bring them to bear against the changelings were the artifacts on their person and not stored in the vault. Indeed, could Twilight have even opened the vault?”

Celestia nodded. “I taught her the security spell.”

“You misunderstand me. The hole in the door is positioned so that you can bow your head and slide in your horn. Could Twilight have managed that feat?”

“Yes. That was part of the lesson.” After a moment, Celestia added, “She does have to rear up to do it.”

Luna smirked. “And how many tries did it take her to manage it?”

Eventually, Celestia said, “A few.”

“I see.”

“We will need Discord, Luna. I have foreseen it.” What for, Celestia didn’t know. All the dream had shown her was his necessity.

“Oh. Well, why did you not say so?”

“You sidetracked me. And I believe you’ve done the same for the whole conversation.”

Luna nodded. “True. Freeing Discord is but a prelude to the true insanity.”

“I’ll send Twilight the journal when she’s a week away from critical mass. I expect her to craft a fixed version by the next day. Once she casts it, it should catalyze her ascension and explain it in one fell swoop.”

“Fell indeed. Suppose she fails as Starswirl did.”

Celestia shook her head. “I have faith in her.”

“And many ponies have faith in us. That does not mean we can perform miracles.” More firmly, Luna said, ”Suppose she fails.”

“We’ll think of something.”

Luna snorted. “You mean I will think of something. As I said earlier, you have the improvisational skill of a block of granite. And what of the other Bearers, forced to live out destinies that are not their own? Why not simply tell Twilight the truth of the Fountain?”

Celestia sighed. “You know why we can’t do that.”

“Normally, yes. But surely if we can trust anypony with this knowledge, that pony is Twilight Sparkle.”

“Normally, I would agree. But the true nature of the Fountain has eluded us since we found it. To tell Twilight of a magical mystery and ask her to neither share nor research it…” Celestia shut her eyes, picturing Twilight’s reaction all too easily. “I would have to order her to do so. She would obey, but it would hurt her terribly.”

“So instead, you will hurt her by tricking her into ruining her best friends’ lives.”

“I am aware of the hypocrisy.”

“So long as you are.” Luna took on a distant look. “And then there is the matter of pitting her against him.”

“He needs to be dealt with, and she to understand what the darkness can do when untempered by moonlight.”

“You would send the Bearers without their Elements.”

“The Tree will need them soon. They can’t rely on them as a crutch.” Celestia’s head dipped as she shut her eyes. “Not like I did.”

Luna nuzzled her. “It was the only choice you could make that would let you live with yourself afterwards. You know I do not blame you.”

“I do.”

“Are you sure you don't want me to go as well?”

“Yes. Princess Cadence and Shining Armor are already there. The others will be joining them soon.” Celestia’s eye flicked to the doors of the throne room. She flicked an ear.

Luna followed her gaze. The Fountain’s light shone through the doors. She rolled her eyes and accounted for possible purple eavesdroppers. “The Empire's magic is powerful. It cannot fall again, my sister.”

“She will succeed at her task. And when she does, we'll know that she is that much closer to being ready.”

The guards opened the doors. Twilight cleared her throat.

Both turned to see her burdened with books, scrolls, and quills. Luna gave Celestia a look that spoke volumes—most especially that the conversation was only paused, not concluded—before walking out of the Hall of Legends. Celestia mentally braced herself to once again ask the world of her student, hoping that this would not be the day Twilight finally said “No.” Or worse, “Why?”

“Trust me, little sister,” she said. Somepony needed to.

The vernal equinox marked the Black Sabbath, Luna’s traditional day of rest as the day took majority from the night. This year, she had chosen to spend it with one of her fellow princesses, conferring on matters meant only for royal ears and alicorn minds.

These matters largely consisted of getting absolutely schnockered.

“Wait. Wait.” Twilight paused, her eyes attempting to blink and doing it out of sync. She tried get her wings back under control; they hadn’t had this much of a mind of their own for years. Once she collected herself, she resumed her thoughtful discourse. “Wait. You’re telling me—“

Luna nodded. “She knew for years. Years.” She poured herself another glass of wine strong enough for an alicorn constitution. One of the less noted properties of the Fountain of Youth, that. “Raced ‘gainst the clock and barely won. Oh, what I would’ve given to see that letter.” She waved a hoof and, in what was likely an attempt at Twilight’s voice, said, “Dear Princess Celestia, I appear to have grown wings. I am unsure what friendship lessons I can derive from them. Please advise.”

Twilight’s giggles undercut her pout. “I do not sound like that.”

“Not anymore, no.”

“But that thing in her thing is really the Thing of Youth?” Twilight gave a few better coordinated blinks as she rebooted her vocabulary. “Fountain?”

Luna nodded. “Oh yes. She, Starswirl, and I found it while hiking o’er the Canterhorn. Put down a warren of Diamond Dogs trying to awaken Lavan the All-Smelter, stopped by a spring on our way back, and the water glowed with magic. Only to alicorn eyes, though.”

“Huh. You know, I’ve seen it, but I always figured she put that in later. Why didn’t she ever tell me?”

“She’d also have to ask you to keep it a secret.”

“Why? Wait. Oh.” Twilight grimaced. ”Yeah, if it turns everypony into alicorns, then… yeah. That’s bad.”

Luna shook her head and had to stop when the vertigo started to set in. “Not everypony. Only those who already have the potential. Still, neither she nor I want ponies lining up by the thousands to dunk their heads and see if they come out of it with extra bits.”

“And she was worried about me spilling the beans?” Twilight laughed, louder and longer than she’d first intended. ”Please. I know how much she’s hiding. Well, maybe I don’t, but I know there’s a lot. I’ve had some of the best security clearance in Canterlot almost since I got my cutie mark. As long as she let me study the stuff, I’d be fine with it.”

“The water loses its magic when taken out of the spring, and I doubt Tia will let you set up your laboratory in the throne room.”

“Oh.” Twilight frowned. “Darn.”

“Friendly reminder, going insane and trying to overthrow Celestia doesn’t work well.”

“I’ll keep that in mind.”

The island was a little dollop of paradise atop beautiful ocean waters. Beautiful beaches, lush vegetation, and a few birds that hadn’t bothered to fly for generations, all unsullied by the hoof of sapience.

Until recently.

“In fairness,” said Luna, “I specifically told her not to go crazy and overthrow you.”

Celestia said nothing, pointedly staring at the sun as only she could.

“I meant it as a joke. She was your faithful student. She all but worshipped the ground you walked on. How was I supposed to know that she would just stay sane during the coup? It is not as though she has a good track record of it.”

Celestia continued to contemplate her cosmic companion.

“And I am still not sure why I had to be banished along with you. Though I will say that if I must be exiled, Polyneighsia is vastly superior to the moon.”

A half-hearted force bolt lashed out and fizzled against the force bubble surrounding the island, specifically keyed to block alicorn magic. Celestia snorted. “Banished and then imprisoned in the place we were banished to.”

Luna tilted her head. “Sorry?”

“Just something I remembered. The Philomena incident.” After a moment, Celestia added, “Specifically, the one in Ponyville.”

“Ah, yes. If nothing else, that brilliant buzzard will be defending your memory even as we speak.”

Celestia turned back to the sun.

“Oh, come on, Tia! She promised not to banish us for longer than a generation. Why, I am sure that before you know it, we will back in the throne room as Twilight begs us to take up the reins of state again.”

“I have only one thing to say to you, dearest sister.”

“And what is that?”

Celestia looked back, smiling. She swept a hoof over the tropical luxury surrounding them. “Just as planned.”

Luna contemplated this. "I have a response, o beloved sister."

"And that would be?"

"Bullshit."

Author's Notes:

For those wondering, the title is based on "The Drop of Honey," another story of how an errant milliliter of fluid can have wide-ranging, long-lasting consequences.