Shining Armor had never seen this part of Canterlot Castle before. It had been so long since his experience in Equestrian leadership that this wasn't a terribly unexpected thing. That didn't make it any easier to pass through vast chambers that had not existed, filled with strange machines of metal and flashing lights with threads of plastic running between them.

Shining probably should have followed the changing state of Equestria more over the last few years. But the older he got, the less any of this made sense. His younger sister had reasons behind it all—reasons behind bringing him here. It was enough that Captain Gallus hadn't thought it necessary to escort him through the castle to his destination. For better or worse, Shining's name still meant something.

They'll be telling stories about the old gray stallion soon enough, if they haven't already started. But whatever might be waiting, Shining Armor wasn't old and feeble yet. He found the memorial hall Twilight had indicated, its somber length filled with statues of the dead. He lowered his head respectfully as he passed a few of them. Honored Leo the Bold, and Moire Pattern with one wing broken even in stony monument.

Soon I'll be one of these in the Crystal Empire. In another century, only my family will remember me.

At the end of the hall he stopped to fish around on the side of an empty grave, and found the indicated lever. Morbid, little sis. Stone ground on stone, and the passage opened for him.

At least everything was built for Alicorn sizes—the spiral staircase was high enough that there was no danger of scraping his horn against it. As he descended he reached a section without sides, opening into a vast space of multicolored crystals. Canterlot Caverns. We were bound to get down here eventually.

The room he arrived in was mostly empty though, with a pair of stone ponies holding spears to form a doorway between them. Their eyes glowed with spots of blue crystal, seeming to watch him as he passed underneath. He felt his fur stand on end as he walked through. He had never matched his sister's magical gifts, but he could sense a powerful defensive spell. The next generation of the shield he had invented so long ago.

Once through, Shining had to do a double-take, his mouth hanging open as he stared. Had his sister managed to work in a teleport so subtle he couldn't feel it?

On the other side of the guards was a laboratory as modern as the fancy photos he sometimes saw from new construction in Manehattan or the Empire, where thaumatech was advancing fastest. Princess Twilight had a miniature version of that, with a single piece of almost every kind of lab equipment he could name and many he didn't recognize.

One apparatus spun, another hummed and churned, microscopes displayed their contents, and beakers boiled. A two-dimensional grid of rolling whiteboards took up the far end of the room, covered so completely in spell diagrams that his eyes blurred them together beyond recognition.

There was only a single exit from the room, separated by a heavy steel blast door as secure as the one on Canterlot Tower. It was open currently, its rusty metal teeth gleaming in the electric lights.

"Big brother, you're here!" Twilight called, waving one hoof from beyond the door. "Over here!"

I am never going to get used to that. His little sister towered over him now, with wings as wide and mane as magical as Celestia. She held all the same responsibilities now, and maybe the same Alicorn magic. Shining was a little weak on his understanding of Imperial magic.

He couldn't hurry over without feeling his fetlocks begin to ache. He ignored it, biting his tongue to suppress the pain. Princess Twilight would be happiest if she never noticed.

His little sister was clearly excited about something, that much was obvious. But since when did she feel the need to share her magical innovations with an old guardspony who wouldn't appreciate them?

He clambered through the security door, noting the crystal stubs emerging from the walls. This wasn't some newly built vault to keep thieves out. All these spells pointed inward.

The chamber itself was a ritual casting circle, more advanced than any he'd ever seen. Six perfect obelisks of the six pure metals surrounded a perfectly flat lower platform. Huge conduits passed between them, along with more of those plastic threads.

Shining did not need his sister's mastery of magic to understand just how much power was flowing through this room. His horn began to ache as his own magical reserves charged from the stray power radiating all around him. With nowhere else to go, the magic would gradually build up into a migraine. Or worse, if a pony were trapped in here.

"Well this is... intense," he said, stopping in the doorway. That way he wouldn't have nearly as far to go when he inevitably made a break for it. "Thought my retirement was too boring even for me, Twily?"

The old nickname felt strange on his tongue when looking up at a creature as magical as his little sister. Her eyes seemed to look right through him, with a confidence and might that went beyond a horn and some wings.

But she wasn't the only one. Another pair of figures stood on the far side of the room, mostly concealed in the shadow of the iron obelisk. But hearing him, they both emerged, and Shining froze.

It was his wife and child.

Though the years had been harsh enough on him to turn his mane grayish and his limbs shriveled, his only child had aged like... every natural Alicorn. Of which she was the only one ever born, but that was beside the point. She looked to him like his little sister had, on the day she was coronated. Shorter than he was, with oversized wings.

His wife was somewhere between her old self and Twilight's current state. But without the magic of sun and moon within her, she'd grown more slowly. They suspected it would take at least a thousand years for her to look like Twilight. Not that it would matter much to Shining either way.

Is this the moment that she tells me it's too weird to be together? Not coming on that last cruise had seemed like a warning sign. But why would she show up with his little sister in a secret lab? Flurry had even less interest in magic than Cadance, and spent almost all of her time in the growing crystal pegasus cloud-city of Prism.

There was only one thing that could bring them all together like this, and it didn't have anything to do with his doomed marriage. "Equestria's in danger," he said, taking a few steps closer to the ring of obelisks. Down on the floor between them was a spell diagram, but not chalked onto the floor in the usual way.

This one was melted into shape, and looked to be made entirely of gold. If he had to guess, it was the same spell he'd seen prototyped on the whiteboard behind him.

"Not exactly," Twilight answered. His wife and daughter both started towards him, but the walkway outside the spell was narrow and neither wanted to go anywhere near it. They didn't move fast. "Though there's something to say for the mental health of its ruling class... and their nepotism. But we've saved Equestria so many times now. Just this once, I get to do something for my family."

That doesn't explain anything. He might've said so to his little sister—but Twilight was an Alicorn now, and the ruler of his whole world. It didn't feel right to make friendly quips with this goddess of endless youth and magic.

Flurry reached him first, gliding over to embrace him too tightly with her massive wings. "Daddy!" she called, her delight louder than the drone of Twilight's thaumic generators.

Thank Celestia you didn't stay a teenager forever. Fading before his children was a natural thing—all ponies went through it before the end. So long as Flurry continued to tolerate him, he could live with that. She had already grown into far more than he ever could've imagined.

"Hello sweetheart." He squirmed free, groaning slightly with the pain. Even when she tried her best, Flurry Heart's strength could be incredible.

"Honey." Cadance was stiffer, and only waved a polite hoof. "I'm sorry I couldn't tell you about this. But it didn't feel right to... get your hopes up, if we couldn't do it."

"That's the reality of research on the cutting edge of magical knowledge," Twilight said, before the silence could get any more awkward. "Today is a gamble too, but now we've gathered together enough data that I'm confident we'll succeed."

"Succeed at what?" He glanced nervously between the three of them, resting one hoof against his aching horn. "I don't have the magical endurance of an Alicorn, so I'd... rather not have much of this conversation in here. Could you tell me about your amazing new discoveries in the lab instead?"

Twilight shook her head, but it was Flurry who spoke first. "This is for you, Dad. You need to go down into the spell, not away from it."

Both the other two turned to glare at her. Flurry winced, ears flattening. But Shining had heard, and his expression grew more cautious. What did she mean?

"This is for me?" He glanced around the room, trying to make sense of any of it. This much magic bordered on the levels an Alicorn needed to raise the sun. It could lift a city up into the sky, or shield it from an invasion for months at a time. "Can't be. Whatever this is—I hate to say it twice, but I'm not an Alicorn. Even when I was young, all this would've been past me. Maybe my spells were stronger than most, but I couldn't reach much further than the rotes in my spellbook. I don't know what this is."

"That's exactly the reason we did this." Princess Cadance stepped towards him, reaching out with a single hoof. Even after all these years, he was still transfixed by her beauty. But while he had once been something of an equal to her, the years had withered him, while she only bloomed brighter than ever.

He twitched reflexively away from her, but managed to hide his shame. He thought.

"If we don't do anything, you're going to keep going like this. We'll lose you... we can't let that happen."

What? He turned away from her, towards where Twilight had taken up position beside a single control panel. It used one of those strange new hoof-twisting devices, clicking with each change she made. "Everypony who ever lived probably wishes that," he said ruefully. "But there aren't very many stories where the ones looking for immortality find it."

"True." Twilight didn't stop what she was doing. As she moved her hooves, the floor in the center of the room pivoted and rotated slowly, moving the glowing obelisks with it. "But that doesn't mean aging is a secured, immovable point. Every pony it takes is something precious lost forever.

"One day, as our understanding of magic grows more advanced, I imagine a future where no pony dies who does not wish to."

"But we couldn't wait that long," Flurry added, popping up beside him again. At least someone wasn't treating him like an unsteady crystal goblet about to fall over. "That's why Twilight has been figuring out a way to make you into an Alicorn princess!"

Shining chuckled in response, patting his daughter lightly on the shoulders. "I don't want to sound like I don't appreciate the sentiment, sweetheart. But that isn't—"

The others weren't laughing too. Cadance and Twilight both looked deadly serious. He went on, "I've been around long enough to know that Alicorns don't work like that. They're chosen by harmony as much as made. It's fate and destiny and stuff. If it were easy, ponies like Sunset Shimmer wouldn't have rebelled."

"Nopony said it was easy," Twilight said, a little of her more familiar sarcasm returning. "Does this room look easy? I had Starswirl's magnum opus as a starting point, and it still took the spare time of the last decade to work all this out. Then there was sourcing the raw materials, and the digital models..."

"It's real, Shiny." Cadance met his eyes, expression deadly serious. "Your sister figured out a way to keep our family together."

He glanced between them, taking in the scope of the spell for the first time. It was for him. A decade of work, for me? As the ruler of Equestria, Twilight could not have much spare time. But instead of seducing suitors or traveling the world or just reading all the fiction written in Equestria, she'd built all this.

"Flurry's right?" he asked. "I walk down into that thing, and walk out an Alicorn? Is that... fair? I have to assume we can't cast this spell very often. If we're going to make somepony immortal, why not someone who matters more? What about that apprentice of yours, Twilight? Give her my spot."

"Starlight? She made herself into a lich years ago, this spell wouldn't work on her."

Before Twilight could say more, or even explain what a lich was, Cadance advanced on him, backing him up against the cavern wall. "We didn't make this for just anypony. You heard your sister—one day, we'll be able to help everyone. But being an Alicorn is more than that.

"It's the selflessness to serve something more. To care about your subjects, to give them hope when there's none left. Shiny, you've been that for me for almost half a century now. This spell is ours to give to you, nobody else."

Shining opened his mouth to argue—then fell silent. He knew that face, his wife wasn't interested in an argument. Besides, as terrifying as the spell was, it was an opportunity. The kind of thing most ponies could only dream of.

I didn't ask for this, I don't have to feel guilty for accepting it. "So ponies were wrong about Alicorns and destiny? All I have to do is walk into the spell and... I walk out immortal? Hopefully... not looking like this for all eternity." He held out one shriveled limb, wincing. "It's harder and harder to look noble for the royal portraits with so many wrinkles."

Twilight winced. "Well, there's... good and bad news for you there, Shining. It's... the reason we're having this conversation, and we didn't just cast the spell. Being able to age isn't something I would consider important to your identity. But becoming an Alicorn princess is more than just agelessness."

"More than just..." He froze, glancing between Twilight and Flurry. That was the second time someone had used that particular description. In Twilight's modern, friendlier Equestria, she even took the time to use inclusive language towards stallions. "What exactly are you asking me to do?"

Now it was the mighty Alicorn struggling to meet his eyes, instead of the other way around. "The magical realities of Alicorns are... complex. It's possible that with more research, I'll understand them better. But we don't have time for that. This spell requires immense strength from the recipient as well as the casters. If we waited much longer..." She didn't finish, but she didn't have to. Shining could read the implication in that silence.

"Alicorns are always female," Twilight said. "When I was researching the history of everyone Equestria has any rumors of... I learned that has always been the case, even for the natural ones. That never meant that the pool of candidates was half as large as it should've been—it meant that those who chose this path sometimes left more of themselves behind than others."

His mouth nearly hit the floor. For a few seconds Shining was momentarily distracted with speculation, imagining which of the ancient Alicorns of myth and story had once been stallions. He couldn't quite figure out if the story were empowering or insulting, but if it was true then it didn’t matter either way.

"How is..." It was his turn to reach over to Cadance, wrapping one arm around her shoulder. She held him there, without flinching at the touch of his old, feeble body. "Is that much better than me being dead? I wouldn't be the same pony anymore. How could you... still love me?"

Even asking that much was a struggle, with both his daughter and his sister here to watch. But if his whole life were about to be rewritten, he couldn't afford to shy away from the most important question.

Cadance was crying now, though he couldn't tell if they were tears of sadness or joy. "Oh, Shiny... do you think it would make a difference to me? I'm the princess of love, and I love you. I don't know if the same will be true for you—but if it is, then I'm prepared to honor the oath I made half a century ago. I'll love the new you just as much as the old."

"Me too!" Flurry added, nuzzling up beside him. "I don't wanna be mean about it, but there was so much we couldn't do together! Once you're an Alicorn, I can show you what Prism is really like! No more peeking at it from balloons and creeping around with a cloudwalking spell. We've done amazing things up there!"

"I'm sure you have." He leaned up, kissing Cadance for perhaps the last time. Certainly the last time looking like himself, anyway. There were plenty of unanswered questions, and fears for what his elevation would do to Equestria. But Twilight was much smarter than he was—if she'd gone this far, she would've thought of all that.

"Alright." He turned back towards the spell. "I'm going to stop asking questions before I run away or the magic in here explodes my head. Let's just... do this. Before I change my mind."