Twilight waved a hoof slowly in front of Celestia, noticing no reaction from the unicorn, who was doing a very good impression of a terrified statue. "Should uh...should we do something?"
"I got this!" Sunset proclaimed, her eyes glinting with mischief as she lit up her horn and conjured up a glowing facsimile of a human hand, which floated it's way towards Celestia before delivering a solid flick against her horn.
It seemed to do the trick as Celestia started, taking a step back and blinking in confusion while a few golden sparks sputtered from the tip of her horn.
"Something you'd like to tell us Principal?" Sunset asked innocently, now that Celestia had been knocked from her state of catatonia. "You seemed pretty worked up upon hearing Princess Cadance's full name."
"I, uh, may have had my own run-ins with a Ms. Cadenza back home..." Celestia explained nervously, glancing from side to side while avoiding the eyes of the other ponies (and bug) in the room. "She sort of...hates me, I think."
“What? Why would she hate you?” Twilight asked with a frown of concern. “She loves everybody...usually...” she added, remembering their current predicament.
“It’s uhh...nothing worth mentioning!” Celestia proclaimed nervously. “Just some inter-school rivalry, Cady...er...Dean Cadance that is, works at a school Canterlot High regularly competes with is all!”
"How is it you're considered a diplomatic mastermind while she can't even tell a decent lie?" Chrysalis asked, turning to look up at Princess Celestia.
"I've had a lot of practice." Princess Celestia admitted with a small sigh and a sympathetic look to her increasingly uncomfortable interdimensional counterpart.
"Hmmm, I'm pretty sure Shining is the only one I've ever heard call Cadance 'Cady" before...and usually only when he thinks no one is listening..." Twilight pointed out suspiciously.
Luna leaned in closer to Celestia, squinting her eyes pensively. "Y'know, it's been thousands of years since I've seen it, but I know that look..."
Celestia began rapidly shaking her head and frantically motioning for her not-sister to shut up.
"...yep, that's definitely Tia's 'I had sex with someone I shouldn't have and don't wanna talk about it' face." Luna said triumphantly with a happy nod.
"WHAT!?" Twilight shrieked, not noticing that everypony else in the room didn't seem too surprised.
"cough cough cradlerobber! cough" Sunset said, poorly miming a coughing fit.
Chrysalis again looked to Princess Celestia, giving her a salacious grin . "Did you...?"
"Thought about it." Princess Celestia answered with a noncommittal shrug.
Twilight shook off a shiver of discomfort at the thought of her mentor and sister-in-law together, trying to collect her thoughts. "Wait so then why do you think she hates you?"
The question caused Celestia to cringe, but at this point it was likely too late to gloss over the finer points of the story. "I was a grad student, she was a freshman, we met at a party and I sort of...took her virginity..."
"Gross..." Twilight groaned.
"I don't know babe, it sounds kinda hot." Sunset admitted, a light blush on her face.
Twilight gave her marefriend a glare in response while neither noticed Chrysalis nodding in agreement.
"That still doesn't really explain why you're afraid of her." Luna pointed out, fairly immune to stories of her sister's sexual escapades at this point, and by extension, Celestia's.
Celestia sighed, seeming to wilt in shame. "She gave me her number after that, wanted to go on a date, and I sort of just avoided her..." she admitted, pressing her front hooves together guiltily. "...I didn't want the whole campus to think I was a cradlerobber." she added, giving Sunset a baleful look. "We haven't been on the best terms since then, even professionally..."
"So that's where those rumors started." Sunset mused, thinking back to her days of fanning the flames under every dirty rumor to make it's way through the halls of Canterlot High. "Wait wait wait! We can use this!" she nearly shouted as her inner high school bully and manipulator began to stir.
"I don't see how this can possibly do anything but make the situation worse." Twilight muttered darkly. Even if it was a Cadance and Celestia from another dimension, she still found the whole thing highly unsettling.
"If Celestia was able to get the other Cadance in bed, she should be able to get under Princess Cadance's skin, and hopefully keep her off-balance and flustered enough that she won't kill us!" Sunset explained brightly, causing Twilight's frown to deepen.
"You do remember she's married right? To my brother." Twilight deadpanned.
"Of course." Sunset nodded. "Which is why it's up to you and me to keep him distracted!"
"There is no way I'm helping another pony seduce my brother's wife." Twilight said flatly, giving Sunset a dangerous look.
"Pleeeeeeease Twi!" Sunset begged, trying to make her eyes look as large and sad as possible. "If you help I'll..." she leaned in to whisper in Twilight's ear, causing the alicorn's wings to shoot open rather dramatically.
"Damn you Shimmer..." Twilight grumbled in a weak and defeated tone. "...fine..."
"Hey! Don't I get a say in this?" Celestia interjected indignantly. "I'm not exactly thrilled at the prospect of reliving a particularly shameful part of my past..." she admitted sadly. In truth she had always regretted the entire debacle, but every attempt to patch things up with her fellow educator had seemed to make things worse.
Acting on a hunch, Sunset turned towards Chrysalis with a devious grin. "Chrysi, do you think you could do me a favor and show Celestia her potential target, were she to accept this little mission?"
Immediately picking up on Sunset's scheme, as she did so love scheming herself, Chrysalis returned Sunset's grin before nodding and bursting into green flames. As the flames receded, standing in Chrysalis' place was a lithe pink alicorn with a mane of purple, magenta, and gold cascading down her long neck. She took a few steps towards Celestia and stretched languidly, flashing her a small smile and what could only be described as bedroom eyes.
"I'm in!" Celestia declared, staring at the fake Cadance as her cheeks turned a bright red.
"...I forgot she could do that..." Princess Celestia mumbled to herself, an equally strong blush covering her own muzzle.
Twilight just slammed a hoof into her face.
~~~~~~~~~~~~~~~~~~~~~~~
With a flash and a thunderclap, Princess Cadance and Shining Armor both appeared in front of the main gates to Canterlot Castle.
"I just don't get it..." Shining pondered, looking over the piece of parchment held in his magic. "Why would Starlight tell us Twilight was in Las Pegasus when she was here in Canterlot the whole time, and why did it take Twilight so long to send us this letter asking us to meet them here?"
"I don't care, as long as we finally get some answers!" Cadance growled as she stalked through the gate and down the entryway, determined to finally track down her targets.
"So none of this strikes you as, I don't know, suspicious?" Shining asked conversationally, looking down to again read through what looked like a very hastily scrawled dinner invitation from his sister and Princess Celestia. When Cadance didn't answer, he tore his gaze from the parchment to glance at her, only to find he was alone, and in a completely different part of the castle. "Uhhhh...Cady?"
"Psssst! Shining!" Came a whisper from an adjoining hallway. "Over here!"
"Twily?" Shining called curiously as he began trotting down the strangely dark hallway. "Where are you? We've been looking for you all day!"
"In here!" The voice called from a nearby door that was halfway ajar.
"What are you doing in here?" Shining asked as he opened the door and walked in, only to find a very dark and seemingly empty room.
"Shining, I just want to say that I'm really sorry about this and it absolutely was not my idea." came Twilight's voice from a corner.
"What...?" was all Shining managed before he was suddenly wrapped up in ropes floating in unfamiliar magic, forcing him into a nearby chair and tying him in place.
As soon as he was secured in place, torches around the room lit up, revealing his sister sitting beside a red and gold colored unicorn he'd never met before. "Twily...what's going on?" he asked with a resigned sigh. Normally being held hostage by his sister would warrant a stronger response, but honestly this was turning into the calmest part of his day so far.
"Well first of all I, uh, wanted you to meet my new marefriend!" Twilight said nervously, gesturing towards the mare next to her, who lifted a hoof to wave sheepishly at him. "Sunset Shimmer, meet Shining Armor, Shining, meet Sunset."
"Hello!" Sunset chirped, mostly just happy their plan was succeeding so far.
Shining raised a brow at his sister. "...as in, the same Sunset Shimmer who robbed you the night of your coronation?"
Twilight's forced smile turned into a grimace. "Uh...yes, that would be her..."
"For the record I did apologize for that." Sunset offered nonchalantly.
Shining looked back and forth between the two for a few moments. "...I have questions. Starting with why am I tied to this chair?"
"Oh that!" Twilight gave a hollow sounding chuckle. "We needed to keep you indisposed while an alternate dimension Celestia tries to seduce Cadance, in the hopes that it will somehow stop her from blowing up the castle when she finds out that two of her closest family members each found love without her help!" she blurted as a few hairs in her mane sprang out into wild curls.
"I'm sorry what now?" Shining asked, even more confused.
"Twilight! You're not supposed to tell him that!" Sunset groaned, losing her oddly chipper demeanor.
"Well I can't just lie to him about it!" Twilight nearly shouted, looking even more unhinged.
"Sooooo another version of Celestia, as in Princess Celestia, is about to try and seduce my wife?" Shining asked slowly, as if puzzling his way through the idea.
The two mares just nodded, bracing for the inevitable freak out and subsequent break out attempt.
Shining sat silently for a few moments, seemingly deep in thought as he sorted out a response. "If...if I promise not to intervene...can I watch?"
"Not you too!" Twilight wailed, slumping onto the ground.
"I told you this was a good plan!' Sunset cheered, as she lifted Shining in her magic, chair and all, and trotted towards the door. "C'mon, if we hurry we won't miss the show!"
"HOW AM I THE ONLY ONE WHO THINKS THIS IS A BAD PLAN!?"