A Few Months Later-

“You want to do WHAT?!” Shining said.

Cadance ran a hoof down her face. Months of tireless searching had yielded no results, and so now she was taking the plunge.

“I want to turn you into a mare, then bring my future-self to our era with a time spell so he can impregnate you. We’ll use the Crystal Heart’s power to ensure the zygote remains fertilized when he goes back to the future, and you’ll carry the foal to term,” Cadance said. “Honestly, I thought I was pretty clear the first time.”

Shining snorted. “Oh, you were clear. I just wanted to make sure I heard right before I called you bonkers!”

She’d sprung it on him right after he’d gotten home from drills. She probably could’ve done it at a better time, maybe waited until he was in a better mood, but honestly, there wasn’t ever going to be a good time to bring this up.

“I’ve explored every other possible alternative before deciding on this,” Cadance went on. “There’s no other way for us to conceive.”

Shining shucked off his armor and put it on a stand beside the wall. “Look, Honey, I’m not going to pretend that I know as much as you about Sombra or Love magic, but this is pretty, well…”

Cadance raised an eyebrow.

Shining chose his words with care. “...drastic. I’m not saying you haven’t looked into alternatives; I’m sure you have! But if you want to convince anypony of this, most of all me, you’re going to have to make one hell of an argument!”

An odd smile crept up on Cadance’s face. “I know.”

The door to their walk-in closet opened with a BANG. Dozens upon dozens of books, scrolls, and loose leaves of parchment suddenly flew out at Cadance’s command. On them were written diagrams, formulas, plans, equations, arrays, graphs, theories, theses, experiments, ramblings, musings, ideas, schemes, observations, postulations, engineerings, all written in Cadance’s neat and tidy script.

Shining stared at the swarm of literature now surrounding them. “Wat.”

“Twilight helped me with my research!” Cadance gestured to the veritable forest circling them. “It’s alphabetized, cited, cross-referenced, and even verified by the Equestrian Arcanaeum. Would you like me to go into detail about all the avenues we’ve explored? Want me to tell you about the lengths we’ve gone to try and spare you from this? Do you need some time to go through our findings, hmm? I’m sure you’ll find it all fascinating.”

Shining opened his mouth, then closed it again. He picked out one of the floating pieces of paper, going over it briefly before looking back up with a blank look.

“...Mind giving me the abridged version?”

Cadance giggled. “The abridged version is that nothing else will work. However, if you want a little bit more, I think I can sum things up.”

Shining nodded.

Cadance set the papers and research down on the floor in stacks. “There’s a biological and magical component to pony conception. The biological component is the combination of reproductive cells within a supporting environment, and the magical component is the love one feels for their mate, which ‘orders’ the fertilized egg to begin the process of cell division. When these two components are present, the mother’s body is signaled to begin releasing the appropriate hormones for gestation, and a pregnancy begins.”

Cadance looked down at the floor. “The biological components in my body are all there. Ovulation is normal, I’m going in and out of season, and conception can technically go off without a hitch. But since Sombra’s curse was powered by hatred—the antithesis of love— neither the fertilized egg nor my body is getting the signal to do anything. The zygote just sits there until it’s absorbed into my endometrial lining, then expelled through the normal menstrual cycle.”

“Hold on.” Shining held up a hoof. “Sombra’s doing this?! How? He’s been dead for years!”

“We think it’s a side effect of a curse he was trying to put on me before he died,” Cadance said. “It probably would’ve done more to me, but the bulk of it was nullified by the Crystal Heart.”

Shining sucked in a breath through clenched teeth. He was pretty learned in magic himself, so he had enough knowledge of curses to connect a few dots.

“What’s the curse’s rate of decay?”

Cadance exhaled out her nose. “Half a percent a year.”

“And when will true conception be possible at that rate?”

She winced. “A century.”

Shining winced as well. “Ouch…”

“Yeah.”

Shining rubbed his chin. “Is there a way to amplify the Crystal Heart’s power? Maybe speed things up a bit?”

Cadance shook her head. “It’s already operating at max, and it’s not like I can just make another one if we break it. Ancient relics don’t exactly grow on trees.”

Shining ran a hoof through his mane. “What about some kind of counter-stasis spell? If Sombra’s was powered by hatred, maybe we could just do the opposite with love—”

“If you think for longer than five seconds, you’ll realize why that’s a terrible idea,” Cadance said. “Even if such a spell existed—which it doesn’t—I really don’t want to be in stasis for one hundred years. Our ponies’ morale would suffer, you’d be in stasis with me so we’d have to have a steward running things, and even after all that there’s not even a guarantee it’d actually work—”

“Okay, I get it,” Shining said. “You’ve clearly given this some thought. But I still don’t see why your solution requires me. If the issue is just magical sterility, why don’t we recruit a surrogate? I know it’s possible to transplant fertilized eggs into others."

“Doctor Endo already did some tests regarding that,” Cadance said. “He found that the curse is bonded to my very essence. Even through a surrogate, the magic would still linger in my cells and prevent gestation. Twilight confirmed it with some tests of her own. It’s not something we can get around.”

And that’s when it all hit Shining like a freight train.

“We really are backed in a corner here, aren’t we?”

Cadance’s eyes grew distant. “Twilight’s the one who suggested the time spell. We summon my future self as a stallion from when the curse has worn off, he provides the genetic material, then use the Crystal Heart to stabilize any temporal irregularities during conception. Brilliant, really...”

Shining mulled all of that over. He didn’t doubt Twilight and Cadance’s research and findings, and the idea of two Cadances was certainly appealing, but…

“I’m still getting hung up on the whole ‘turn me into a mare and knock me up thing.’”

Cadance gave him a funny look, her eyes flickering down a moment. “I know for a fact that this idea has got you more than a little intrigued... or do you have a boner for some other reason?”

Shining was beginning to sweat. He didn’t deny anything, particularly not the reason why his stallionhood was free of its sheath and throbbing with his heartbeat.

“No fair,” he grumbled.

“Nothing about this is fair,” Cadance replied. She glanced at his cock again and licked her lips. “Though I’m happy you’re interested, at least...”

Shining looked away. “L-Look, fantasies are one thing; but reality’s quite another! I’m not sure I—”

“Twilight and I have found several spells that will help with the more uncomfortable parts of pregnancy,” said Cadance. “Nausea suppression, heartburn relief, malleable skin tissue, reinforced bladder, better blood flow, improved circulation, that sort of thing! It’ll be a cakewalk.”

“You’re asking me to abandon my bloody gender for a year!” Shining burst out. "A part of who I am! My identity!”

Cadance went to him and put a hoof on his cheek. “Once the baby’s born, you can go back to being a super-macho stallion. Does eleven and a half months really seem like that long a time?”

Shining didn’t react to her touch, but neither did he shy away. “...I didn’t think that swapping genders a few times to spice up the sex would lead to something like this.”

“Hey, I’d still be frantically searching for a cure if you hadn’t gotten curious about the other side of the fence.”

Shining face reddened. “W-Well, I’d be lying if I said I didn’t enjoy our… ‘experiments,’ but this is way, way different! This is a home run when our little sessions have been hits to first or second base!”

Cadance circled around him with a coy look. “I seem to recall you saying several things to the contrary...”

Shining hesitated, but then shook his head back and forth. “That was in the heat of the moment. I was just trying to get you riled up!”

“‘Do it inside, Eros!’” Cadance said in a deep, erotic moan. “Yes! I want it all! Give it to me! Let me have your foals!”

“Heat. Of. The. Moment,” Shining said through clenched teeth. His breathing was shallow, his cock twitching below. “Nothing more, nothing less.”

Cadance crossed her hooves. “I think the Princess of Love can tell the difference between sexual banter and actual desire. Whether you’re aware of it or not, there’s a part of you that very much wants this, and it comes out strong when you’re a mare.”

Shining swallowed hard. He was running out of things to hide behind, and it was clear that Cadance was ready for whatever excuse or problem he could bring up.

“What about labor and foaling?”

“Pain-to-Pleasure spell,” Cadance said. “We cast it once your water breaks, and your contractions suddenly feel like having sex. You’ll have the best orgasms of your life.”

Shining bit his lip. “I thought that that spell was dangerous.”

“If a normal pony tries to cast it,” Cadance said. “But your sister and I aren’t normal ponies, are we?”

Shining’s eyes flitted back and forth. It all seemed insane, but deep down inside he’d pretty much already made a decision. His sense of duty had pretty much sealed the deal from the start.

“What are we going to say to everypony? Especially the new recruits!” Shining adopted a mocking tone. “Hey guys, Shining Armor’s gonna turn into a mare and have a foal! Don’t mind that, though! Keep doing push-ups!”

Cadance shrugged. “I doubt anypony’s gonna care too much. Besides, it’s not the craziest thing that’s happened since the Empire’s returned. Remember the dafflewarks? Hmm? Recall that little escapade?”

“Yes, well… um…” Shining put a hoof behind his head. “W-What about the rest of Equestria? They’re gonna have a field day with this!”

Cadance threw her hooves in the air. “Who gives a damn? They’re not the ones with the problem! Celestia’s sake, I’ll handle the press myself if you’re so concerned about the rest of the world!”

“But what about—”

“Do you want foals or not?!”

“YES!” Shining stamped his hoof. “Gods, yes! I want them more than anything else, and I want to have them with you!”

“THEN LISTEN TO WHAT I’M SAYING!” Cadance shouted. “I! AM! BARREN! No sons, no daughters, no nothing! How about you explain THAT to Equestria?! See how well that goes over!”

“...”

“Your sister and I have tried everything we can think of to try and spare you from this, but the bottom line is that there’s no other way!” Cadance’s eyes were glistening. “The only way you’re gonna have a kid with me is if you get knocked up yourself, because by the time this curse wears off, you’ll be DEAD and BURIED!”

“All right, all right, I get it!” Shining looked away from her watery gaze. “You’ve made your point! Sheesh… I’m just… I’m just a little scared, you know? I wanted to make sure that you’d thought this through.”

Cadance snorted. “More than anything else in my life.”

Shining said nothing. He walked over to a full-length mirror to examine himself: his square and chiseled muzzle, his broad chest, his thick and sturdy legs, his trim and stocky frame. His athletic body reflected the long years of his successful military career. He was big, handsome, and strong, a towering stallion and a prime example of his race.

All of that would change. Everything would be reshaped and modified for a completely different purpose.

Cadance walked up behind him. Her face was neutral as she put a wing around him.

“In the long run, nopony’s even going to remember that you did this. It’ll just be remembered as another heroic act you did, and before long, it’ll be overshadowed by other amazing things.”

Shining clicked his teeth. Did he need more time to think about it? Maybe mull it over for a while? He supposed it wouldn’t hurt to go and get someone else’s advice, but the longer he stalled, the worse it was gonna wind up being.

Shining sighed and nuzzled Cadance’s cheek. “You owe me big time for this.”

Cadance giggled and nuzzled him back. “Trust me, I’ve got a few things planned you’ll enjoy.”

Yeah, it was a huge commitment, but Shining supposed it’d be worth it in the end. And considering the reasons for doing it in the first place, he doubted it’d do much to his image. He just had to grin and bear it for a while.

Goody, goody.