Despite its profound implications, it was a simple question.
Sunburst had first asked it to himself, some days ago, when reviewing the Crystal Empire’s spell archives. Starlight Glimmer had submitted her age-reversal spell for study several weeks prior, after using it in a poorly-conceived stunt to relive their foalhood friendship. He’d shelved it without any further inquiry, as he had not thought it especially unusual at the time. While age reversal spells were among the most advanced spells known to ponykind, they were not beyond the pale of Equestria’s highest-level unicorns.
But, as his job left him woefully bored as usual, he decided on a whim to look at the spell Starlight had written.
Most age-altering spells had only a temporary effect. After the effect wore off, the subject would revert to the age they’d started as before, plus whatever time had passed with the spell still active. This way, it was impossible to use age magic to retain one’s youth, no matter how skilled or powerful the spellcaster was.
Starlight’s spell did not have that restriction. Its effects were permanent, and could only be undone by casting the same spell to age the target in the opposite direction. Now, as Starlight stood before him in the Imperial Crystal Library, she was left to consider the same question.
“I’m sorry, what?”
“Did you discover the secret to immortality?” Sunburst repeated. “Because looking at this spell you’ve written, that’s exactly what you’ve done. You’ve found a way to permanently reverse aging.”
Starlight gave a nervous giggle. “Oh, Sunburst, you’re such a joker! Here, let me take a look.” Her horn became enveloped in a light glow, and she pulled the scroll of parchment from Sunburst’s own telekinetic grasp. “I can assure you, there’s nothing of the sort... here...”
As she read over the spell, Starlight’s face went pale.
“Well?”
Starlight’s mouth worked itself silently, before finding the proper words. “I, uh... Okay, so it looks like I did do that. But surely it’s not such a big deal that you had to call me all the way up here, right?”
“Not a big deal!? You’ve discovered the secret to immortality!”
Starlight jumped forward, cramming a hoof into Sunburst’s mouth. “Shh! Not so loud!”
“Mfff! Mmm!” With a forceful ptooey, Sunburst spit out the appendage that just narrowly avoided breaking his teeth. “Starlight. You understand just how big this is, don’t you? This sort of magic could radically transform society as we know it!”
“I know, I know!” Starlight replied in a hushed tone. “That’s why you have to keep it secret! If ponies start to learn there’s a way to keep them from dying, they’ll stop at nothing to get their hooves on it! And there’s no telling what sort of social turmoil that would cause!”
“But what exactly do you propose we do?” said Sunburst. “We can’t just destroy this spell. We’d be losing some of the most precious knowledge in the entire world!”
Starlight’s hoof slapped sharply against her forehead. “Of course you’d say that. But just how exactly are we supposed to keep this spell safe?”
Sunburst tapped a hoof to his chin, his brow furrowing in thought. “Well... what about Princess Twilight? She used to be a librarian, and she’s dealt with a lot of things that threatened Equestria’s stability. Maybe we could ask her?”
“I dunno...” Starlight looked unsure of herself for a moment. “...then again, I guess there probably isn’t any better pony we can tell about it.”
“So you’ll tell her, then?”
“Yeah,” said Starlight. “I just hope her reaction isn’t too overblown...”
————————
“WHAAAAAAAAAAAAAAT!?”
“So much for that,” Starlight groaned. “Twilight please, it’s not a big de—”
“Not a big deal!? You’ve discovered the secret to immortality!”
Twilight paced back and forth, her hooves pattering loudly against the floor of her castle library. “Do you have any idea just what it is you’ve shown me here?” she said. “If word of this gets out, it will be total chaos! Ponies all across Equestria will demand we use this spell to keep them young! And there’s no telling what kind of conflicts could arise from being able to extend lives indefinitely! Ponies have literally killed each other seeking eternal youth!”
“You mean the war for the Holy Trough?” said Starlight. “Wasn’t that more than eleven hundred years ago?”
“That doesn’t matter!” said Twilight. “The point is, this sort of spell being leaked to the general public could send all of Equestria into utter chaos! What were you thinking coming up with a spell like this!?”
Starlight bit her lower lip. “Um... I wasn’t?”
Twilight blinked. “What?”
“I, um... never intended my spell to be used for immortality? It just sort of worked like that?”
“You discovered the secret to immortality by accident!?”
“H-hey! Twilight, calm down!” Starlight hurriedly cut in. “Look, I know it sounds bad, but that’s why I need your advice! You’re more familiar with this immortality stuff than I am!”
“Why would I be familiar with immortality!?”
Starlight turned to Sunburst, and the two of them shared a look.
“Well, uh,” said Sunburst, “you’re an alicorn. Aren’t you?”
“Obviously,” said Twilight. “But what does that have to do with anything?”
Starlight shared another look with Sunburst. “But that makes you immortal, doesn’t it?”
“What? No!” Twilight shot back. “Why does everypony always ask me that? Princess Celestia and Princess Luna are the only known immortals in Equestria, and nopony even knows how they do it! It has nothing to do with being an alicorn!”
“There’s no need to yell at me,” Starlight weakly protested. “But if you don’t know anything about immortality, then what exactly are we going to do about this spell? We can’t just leave it and hope nopony discovers it.”
“And destroying it’s definitely out of the question,” said Sunburst. “It just... seems wrong, as an archivist.”
Twilight gave a small sigh. “I know the feeling,” she said. “Look, this whole spell is something that’s way bigger than me. There’s only one pony I can trust to guide us in a situation like this.”
Starlight’s eyes briefly widened. “You don’t mean...”
Twilight nodded. “We’re going to have to tell Princess Celestia.”
————————
The door to Royal Sisters’ throne room slammed shut with nearly deafening noise and force. It was here, after word of her discovery had been sent, that Starlight Glimmer had been called. The afternoon sun shone down over Canterlot, sending golden streams of light through the stained-glass windows.
Looking towards the end of the room, where Celestia and Luna both sat on their respective thrones, Starlight couldn’t help but feel alone. Though both the Princesses were with her, they had seemed utterly distant from where they sat, projecting an aura of radiance and elegance above and beyond that of other ponies. Princess Celestia had insisted that nobody else come with Starlight, and nowhere was it more apparent than here.
Starlight approached the twin thrones, unable to conceal the trembling in her voice. “Y-y-you called for me, Your Highness? I mean, Your Highnesses? I mean—”
Princess Celestia smiled warmly. “You may relax, Starlight Glimmer. You’re certainly not in trouble, if that’s what you were wondering.”
Starlight managed a nervous laugh. “Oh, well, that’s a relief. Wait, I’m not?”
“Oh no, not at all,” Celestia replied. “In fact, there is something very important I have in mind for you. As the one who guards the secret of immortality, are you prepared to accept the responsibilities that come with it?”
“I...” Starlight hesitated, feeling her voice catch in her throat. “...yes?”
“Excellent,” said Celestia. “Luna, if you would be so kind as to prepare the spell?”
Luna turned to meet her sister’s eyes, and gave a nod. She then turned to face Starlight, and at once Luna’s horn erupted into a blazing light, overflowing with magic that tingled across all of Starlight’s senses. Celestia then joined in with her own spell, and Starlight was nigh-blinded by the sheer force of radiant magic. Shutting her eyes to shield herself from the light, she felt herself enveloped by a strange sensation, like the warmth of a cozy blanket in the winter, woven with the gentle glow of the stars.
When the sensation finally faded, something felt... different. Starlight couldn’t explain what it was, but she felt radically transformed, like something far beyond what she was just moments before. She opened her eyes, and to her shock, found herself standing almost twice as tall as before. Out of curiosity, she turned around to look herself over, and what she saw nearly caused her heart to jump out of her chest.
Silver regalia now adorned her body, decorating her hooves and chest, and her mane had now taken on a flowing, ethereal quality, blowing in a wind that wasn’t there. But even more startling were the pair of wings that now adorned her back.
“Welcome home,” said Celestia, “Princess Starlight Glimmer.”
Starlight’s jaw dropped so hard she could almost swear she felt it unhinged. No matter how she worked her mouth, she struggled to find even the simplest of words to express herself. “I... buh... whuh... p-p-p-p-princess!?”
Luna shook her head, a thin frown written across her muzzle. “Don’t look at me. It was my sister’s idea.”
“But why!? Why a princess!? Why me!?”
Celestia’s smile did not fade. Looking at it now, Starlight could only find it more inscrutable and distant than ever. “It’s quite simple, really. Once you discovered our secret, we decided this was the best way to cover it up, and ensure you remained close to us.”
“Cover it up? What do you...” A sudden realization struck Starlight, causing her words to die before she could even finish speaking them. “...Wait. No. You don’t mean...”
Celestia giggled lightly, covering her mouth with a hoof. “Of course. You didn’t think we’d lived this long naturally, did you?”
