The morning sun shone gently through the thick curtains of the Canterlot castle guest bedroom as Twilight Sparkle stirred beneath the sheets. Sloth. It was a vice she had long missed, and spending a few leisurely days back in Canterlot with Celestia was just what she needed. Time to reconnect with her fellow princesses relaxed her nearly as well as spending time with her friends in the spa. Plus, she was going to play with Flurry Heart this afternoon, as Cadence had managed to ‘coincidentally’ schedule a trip to Canterlot too.

She took a quick peek between nearly closed eyelids to make sure Spike’s bed was empty, just in case. He had a dawn playdate with Flurry Heart down in the vast castle gardens, and since he was gone as scheduled, Princess Twilight Sparkle had a few more treasured moments to reign over her slumber before she had to get up for anything.

Still, the dream she had last night bothered her.

In the chaos and whirl of images, there had been some sort of cramping sensation, much worse than she had ever experienced before, and growing until it had vanished in the brief feeling of relief and emptiness. She had drifted back to sleep afterwards, but now that she was thinking about it, there was something damp on her hind legs, much the same as—

Oh, no. I haven’t wet the bed since I was a foal!

Twilight Sparkle fractionally shifted position in her cloud-soft bed, which was probably some sort of priceless antique which would never be able to be replaced after being soiled. Princess Celestia would be so upset, and everybody in Canterlot would know about her failure. Even Spike would be embarrassed, and he had not worn diapers in nearly a decade. Twilight screwed her eyes closed, trying not to look at the incriminating wet spot, but an unexpected bumping of a damp object around her hind legs made her eyes pop open regardless.

It was an egg.

She blinked.

It was still an egg. Much the same as the freshly laid chicken egg she had once collected for Fluttershy from her brood, it was slightly damp and glistening, but quite unlike the egg, it was a light violet in color and had her cutie mark emblazoned on the side. Also, quite unlike a chicken egg, it was huge, quite nearly the size of a—

Twilight blinked again. Not wanting to believe her traitorous eyes, she reached down with one forehoof and touched the foal-sized ovoid, feeling the blood-warmth of the impossible egg and giving it a nudge to evaluate its probable density.

It was unmistakably an egg.

In one regard, Twilight Sparkle was relieved she had not wet the bed.

In all other regards…

“Keep it together, Twilight,” she whispered. “There has to be a reason there’s an egg in your bed. Other than the obvious one, of course.”

She tucked her tail in against her damp nethers and tried not to think of how that huge object had theoretically managed to transit that narrow passage without waking her up. Even though it had. And somehow she had gone back to sleep afterwards. Until now.

Although pony reproduction had always been an uncomfortable topic for Twilight Sparkle, she was aware of the basics. The bare basics. The somewhat-sketchy process between mare-meets-colt and the delivery room had always been a topic she had avoided in her studies, except for foal development in the womb and infant care outside. The process of going from inside to outside, as well as the actual… act of reproduction, were much like a visual blind spot to her.

Still, she knew one thing for certain: ponies did not lay eggs.

Dragons laid eggs and hatched them by pouring dragonfire across them, thus triggering the magical process of birth. Birds laid eggs and hatched them by holding them close for several weeks as the little birds grew inside the shells. Lizards even laid eggs and hatched them on warm rocks where Celestia’s sun could incubate them.

Alicorns, however…

Twilight Sparkle had never seen nor heard about alicorns reproducing by way of eggs, but with such a small sample size and only two data points less than a thousand years old, it could have been missed. Celestia had been suspiciously vague about where Luna and she had come from, and claimed Cadence had been discovered as a foal. Twilight’s own experience with becoming an alicorn was singularly unique, as even Starswirl the Bearded had not been able to master the unfinished spell which had transformed her into an alicorn, so she had always thought of herself as an outlier, a data point on the graph outside of the very short line.

Still, she was part of the rapidly-growing sample set. After nearly a thousand years of Equestria only knowing one alicorn, the world had adjusted to two, then three, and now four with little Flurry Heart. No, five. Twilight had forgotten to count herself again.

As a student, Twilight Sparkle had once asked Princess Celestia just why Cadence had come to be an alicorn. She said Harmony determined the number of alicorns needed in the world, and if Harmony was concerned about upcoming troubles, more alicorns would appear to help deal with it.

Twilight Sparkle regarded the damp egg and considered her error in neglecting to ask just how Harmony was supposed to provide these additional alicorns. She had brushed the question aside at the time, perhaps due to some faint sense of dread about Princess Celestia launching into a lecture about metaphorical birds and bees. It had not seemed very important at the time, since Twilight was still filled with the childish confidence in the abilities of one very old and wise alicorn and one young and loving foalsitter, who between them would most certainly have been able to vanquish any possible foes, from ancient beasts out of legends to invisible monsters who liked to hide in the shadows under her bed and who could only be vanquished by a second⁽*⁾ bedtime story.
(*) Or three in extremely rare circumstances, with a cookie.

Her curiosity about the origin of alicorns had resurfaced recently with the birth of her niece, Flurry Heart, because the time frame between Cadence revealing her pregnancy and the sudden appearance of her foal had been suspiciously short, and also contained one obvious erroneous data point. It was a research project Twilight was looking forward to, which would involve a great deal of cuddling and playing with the adorable little bundle of joy (and possibly a full suit of enchanted armor for protection), but she had been unable to get more than an hour reserved out of the newest royal foal’s very busy schedule this afternoon. Which, in hindsight, was several hours too late.

She had tried to ask Cadence about the birth in a somewhat indirect fashion specifically worded to avoid the Alicorn of Love’s tendency to be far, far too direct about those kinds of questions, but all her sister-in-law had done was smile and say, “It was magic, Twilight.”

Twilight ran a hoof over the damp surface of the warm egg, shifting in her soiled bed in order to hold it closer. This could not be happening to her without a reason. The world was gaining a lot of alicorns in a hurry. There had to be something truly terrible out there which would need more magic to defeat it, and Harmony had found Twilight Sparkle worthy of the responsibility. The thought calmed her rapidly beating heart and made Twilight light up her horn to cast a life-detection spell on the warm egg.

As she suspected and feared, it was an alicorn. No, she was an alicorn.

Twilight took a deep breath. She was the Element of Magic, but this problem was no longer just hers. An infant alicorn could tip some unseen balance of power, preventing or causing untold devastation. Her own mother had once told her about mares holding the responsibility for making the world survive, as only mares could bring forth life. Motherhood in itself was a great responsibility, but this was far, far greater, and as much as Twilight thought she was not up to it, she had to be. Not for her, but for the life entrusted to her care, and all of Equestria.

She leaned up to press her horn against the egg and whispered, “I don’t know if you can hear me in there, but your mother is right here. I won’t let anything happen to you.”

The egg felt cooler for some reason, and Twilight repeated the life-detection spell as before. An icy force seemed to slug her in the gut as the spell returned a fainter signal, indicating the life-force inside was failing.

“Oh, no,” she whispered, repeating the spell and finding the life it showed even fainter than before. The infant alicorn in the egg was fading fast. There was only one thing Twilight Sparkle could do, and it would have to be now!