Author's Note

So I don’t really feel like making a whole introduction chapter to this whole alternate universe but I will give a summary of the events:

The Mane Six and Fairly Odd Trio are all friends with each other.

Equestria has been conjoined with Fairy World and Dimmsdale.

Timmy’s parents lost custody of him and now Cosmo and Wanda are his sole guardians.

The fairies still have great powers but they aren’t exactly Discord levels of phenomenal now that the worlds have merged.

Also just so we’re clear, I won’t be going over every single scene in the episode unless it’s important. So if a scene is missing, assume it went the same as canon.

Canterlot Wedding Part 1

The Mane Six, Cosmo, Wanda, and Timmy were all enjoying a picnic together near the grasslands overlooking Canterlot.

“Ah, It is gorgeous out. Just gorgeous!” Rarity sighed happily as Applejack drank some water before footsteps were heard which Twilight noticed and saw that Spike was running right towards her.

“Twi... light! ...I... have... Lemme just...” Spike began breathing heavily before he belched out a letter which Twilight was quick to levitate to her eye line so she could read it.

“Dear Twilight, I am sure you are as excited as I am about the upcoming wedding in Canterlot.” Twilight began reading before asking, “Wedding?”

“Don’t look at me.” Timmy shrugged. “I didn’t know about this.”

“Oh riiiiiiiiiiiight, the wedding.” Cosmo chuckled before taking a flyer out of his hair, “Funny thing really? I was gonna tell you guys about this.”

Cosmo then coughed into his hand but before he could speak, Wanda stopped him.

“Maybe we should let Twilight continue.” Wanda put a finger to her husband’s mouth, “Whenever you read news from the Princess you act all dramatic about it.”

“Ugh, I do no such thing.” Cosmo scoffed furiously but Wanda and Timmy just roll their eyes.

“I will be presiding over the ceremony, but would very much like you and your friends to help with the preparations for this wonderful occasion. Fluttershy, I would like you and your songbird choir to provide the music.” Twilight continued reading.

“Oh my goodness! What an honor!” Fluttershy turned to her friends happily.

“Pinkie Pie, I can think of no one more qualified than you to host the reception.”

Pinkie immediately began cheering in excitement as she did a cartwheel.

“Applejack, you will be in charge of the catering for the reception.”

“Well color me pleased as punch.” Applejack smirked in satisfaction.

“Rainbow Dash,” Twilight began and immediately Rainbow Dash began to yawn much to Wanda’s disapproval, “would very much appreciate it if you could perform a sonic rainboom as the bride and groom complete their ‘I do's.”

“YES!” Rainbow Dash cheered before giving Timmy a hi-five.

“Rarity, you will be responsible for designing the dresses for the bride and her bridesmaids.”

Rarity began to speak unintelligibly in excitement before Fluttershy caught her as she fainted.

“And as for you Twilight, you, Cosmo, and Wanda will be playing the most important role of all: Making sure that everything goes as planned. See you all very soon. Yours, Princess Celestia.” Twilight finished before looking on in confusion, “But... I don't understand. Who's getting married?”

“Ooh, I know who’s getting married.” Cosmo began smiling but before he could talk, Wanda clamped his lips shut.

“Oh… I probably should’ve given you this letter first.” Spike said with an awkward smile before Twilight took the letter in her magical aura.

“Princess Celestia cordially invites you to the wedding of Princess Mi Amore Cadenza and...” Twilight gasped. “My brother?!”

“BUM BUM BUM!” Cosmo cried dramatically.

“Not a good time Cosmo.” Timmy whispered warily to his godfather.

(After theme song)

“Your brother’s getting married?” Wanda asked happily, trying to lighten the mood, “Congratulations Twilight, you must be so proud.”

“Yeah, so proud.” Twilight rolled her eyes in annoyance, “So proud that I got this news from a wedding invitation. Not from my brother, but from a piece of paper. Thanks a lot Shining Armor.”

“That seems kinda unreasonable.” Cosmo tried to calm Twilight down, “I mean, it’s just your brother getting married to somepony who’ll be your new sibling in law who you might not even know and… oh…”

“Exactly; and who the hoof is Princess Mi Amore Cadenza?!” Twilight asked angrily.

“Um, Twilight? Are you okay?” Fluttershy asked softly.

“Sorry, it's just that Shining Armor and I have always been so close. He's my B.B.B.F.F!” Twilight sighed sadly. When she saw the confused looks on the Mane Five, Cosmo, Wanda, and Timmy, she immediately clarified, “Big Brother Best Friend Forever.”

“Ohhhhhhhhhhh.” The group realized.

“Before I came here and learned the importance of friendship, Shining Armor was the only pony I ever really accepted as a friend.” Twilight explained.

https://youtu.be/ARBEOoTmOmg?si=TeIwxnIdR6NyeJl3

After Twilight finished singing, Timmy gave Cosmo and Wanda an awkward look, “Not gonna lie, it still weirds me out that they can burst into song.” Timmy whispered to his fairies.

Applejack then walked over to Twilight, “As one of your P.F.Fs,” the farm pony began before she got confused looks from the others, “Pony Friends Forever.” She clarified.

“Ohhhhhhhhh.” The others realized with Timmy adding, “Wait, four of us aren’t ponies…”

“I wanna tell you that I think your brother sounds like a real good guy.” Applejack reassured Twilight regardless.

“He is pretty special. They don’t just let anypony be captain of the royal guard.” Twilight said softly.

“So let me get this straight. We're helping out with the wedding of not only a princess, but a captain of the Royal Guard?” Rarity chirped.

“Guess we are.” Twilight shrugged solemnly.

Rarity fainted in bliss to which Wanda poofed in a pillow to cushion her fall, unamused as the rest of Twilight’s friends began happily talking about how excited they were about the wedding.

“Hey… how are you doing?” Timmy asked Twilight in concern.

“Not too well if I’m being honest.” Twilight told the buck toothed kid sadly causing Timmy to give a look of sympathy.

Later on, the group were all on the train to Canterlot as Rainbow Dash began voicing her excitement once more, “A sonic rainboom? At a wedding?! Can you say "best wedding ever"?!”

Pinkie and Cosmo began to breathe in before the train went through a tunnel, “BEST WEDDING EVER!” The two goofballs echoed until after the train exited the cave.

“So you all get to help with the big fancy wedding, but I'm the one who gets to host the bachelor party! I have just one question. What's a bachelor party?“ Spike bragged before speaking in confusion.

Timmy and Cosmo laughed, clearly amused by Spike’s antics to which he smiled at, knowing they were just having fun.

Meanwhile, Twilight was looking longingly out the window before Wanda floated next to her, “Still upset?” She asked sympathetically.

“I'm just thinking about Shining Armor. Ever since I moved to Ponyville, we've been seeing each other less and less. And now that he's starting a new family with this "Princess Mi Amore Ca-whatshername", we'll probably never see each other.” Twilight vented solemnly.

“Aw cheer up Twilight,” Wanda smiled reassuringly, “Your his sister, he’ll always make time for you.”

“But… you know what happened with Timmy and his paren-“ Twilight began before Wanda covered the unicorn’s mouth.

“That situation was different. Timmy’s parents were neglectful because they chose to be, you and Shining Armor were separated due to circumstances.” Wanda reminded her friend.

We then see the train make it to Canterlot and then phase through a force field much to the shock of all ten heroes.

Once they exited the train, they were shocked to find guards stationed everywhere.

“Whoa, what's with all the guards?” Rainbow Dash asked curiously.

“I’m sure they’re just taking extra precautions. Royal weddings do bring out the strangest ponies.” Rarity explained, “Now let’s get going, we have work to do.”

“And you have a brother to congratulate.” Applejack smiled at Twilight.

“Yeah, congratulate and give a piece of my mind.” Twilight grunted in annoyance as she passed the guards.

“Uh… I’m gonna go follow her.” Cosmo said warily.

“So you can get out of working?” Wanda asked with a scoff.

“You know me so well!” Cosmo said happily before he began floating after Twilight.

Shining Armor was commanding the guards to their posts when he heard the angry voice of Twilight, “I’ve got something to say to you mister.”

The guards brandished their spears much to Cosmo’s fear causing him to immediately hide behind Twilight, “Twily!” Shining Armor said happily before running down to greet her, “Twily! Ah, I've missed, you, kid. How was the train ride? I–”

But Twilight didn’t deter from her angered state, “How dare you not tell me in person that you were getting married! I'm your sister, for pony's sake!”

“It's not my fault! Princess Celestia has requested a major increase in security. Didn't you see all the guards at the train station?” Shining Armor began explaining himself.

“Oh yeah, there’s a big wedding coming up.” You probably heard about it.” Cosmo chirped obliviously before realizing he was talking to the groom and smiled nervously.

“It has nothing to do with the wedding. A threat has been made against Canterlot. We don't know who's responsible for it, but Princess Celestia asked that I help provide additional protection. This, you need to see.” Shining Armor explained before blasting the pink barrier surrounding Canterlot, strengthening it much to Cosmo’s awe before he and Twilight showed concern at Shining Armor’s migraine but he quickly shook it off and continued explaining, “The burden of keeping Canterlot safe and secure rests squarely on my shoulders. Staying focused on the task at hand has been my top priority.”

Shining Armor, Twilight, and Cosmo then made it to the top of the outside castle bridge to which Twilight gave a more understanding look, “Okay, okay, I get it. You've got a really important job protecting all of Canterlot with a force field only you can conjure up. But still... how could you not tell me about something as big as your wedding? Am I not that important to you any more?” Twilight asked sadly.

“Hey. You're my little sister. Of course you're important to me. But I'd understand if you didn't want to be my best mare now.” Shining Armor said happily in a teasing tone, much to Twilight’s glee.

“You want me to be your best mare?” Twilight asked happily.

“Well yeah.” Shining Armor smiled back.

“I’d be honored.” Twilight embraced Shining Armor before pulling away, still a little miffed, “But I'm still pretty ticked you're marrying somepony I don't even know! When did you even meet this "Princess Mi Amore Cadenza"?”

“Twily, Princess Mi Amore Cadenza is Cadance, your old foalsitter.“ Shining Armor replied happily.

“Cadance? As in the Cadance? As in the greatest foalsitter in all the history of foalsitters?!” Twilight asked happily.

“Why are you asking, she’s your foalsitter?” Cosmo asked, clearly confused.

“How many unicorns can just spread love wherever they go? I only know of one! And you're marrying her! You're marrying Cadence! You're marrying Cadence!” Twilight said giddily before the alicorn herself walked in with a grumpy look on her face.

“I hope I'm not interrupting anything important.” Cadence said with an incredulous look.

“Cadence! Sunshine, sunshine, ladybugs awake! Clap your hooves and do a little shake!” Twilight began chanting and then shaking her tail much to Cosmo’s amusement as he began laughing hysterically.

“What are you doing?” Cadence raised an eyebrow.

“Cadence, it’s me. Twilight.” Twilight smiled excitedly but all Cadence did was hum in disinterest before moving to Shining Armor’s side.

“I've gotta get back to my station, but Cadence will be checking in with all of you to see how things are going. I think I speak for both of us when I say we couldn't be more excited to have you here. Right, dear?” Shining Armor smiled at his sister.

“Absolutely.” Cadence gave a sinister smirk, much to Twilight and Cosmo’s confusion.

“Well… we’ll let you get to it.” Shining Armor said before he and Cadence walked off.

“I don’t think Cadence is that happy to see us.” Cosmo whispered to Twilight.

Twilight, Cosmo, and Wanda then went to see Applejack work in the kitchen, “Cake, check. Ice sculpture, check. Best darn bite sized Apple Fritters you ever darn tasted…”

Applejack then shoved one into Cosmo’s mouth who hummed in delight after swallowing it, “Check.” The green haired fairy checked off the list.

“I do, do you?” Spike asked in a faux masculine voice as he played with the Shining Armor soap sculpture.

“I do.” Timmy said in a feminine voice before the two of them began smushing them together as if they were kissing before Twilight levitated them away causing them to nervously laugh.

Soon Princess Cadence walked in much to Applejack’s glee, “Well howdy princess.”

“Please, call me Princess Mi Amore Cadenza.” Cadence replied snootily much to Twilight and Cosmo’s shared annoyance.

“Howdy, Princess Mi Amore Cadenza. You come to check out what's on the menu for your big day?” Applejack asked curiously.

“I have.” Cadence smiled before it morphed into a frown much to Twilight’s suspicion and Cosmo and Wanda’s confusion.

Cadence then levitated an apple fritter to her mouth with a green magical aura before tasting it, “Delicious. I love love love it.” She said in an overly peppy voice.

“Aw shucks, why don’t you take a few to go?” Applejack asked kindly.

Cadence seemed disgusted but took the bag in her magical aura anyway, but what Applejack didn’t see was Cadence immediately throw the fritters into the trash but Twilight, Cosmo, and Wanda did, Spike and Timmy were still playing with the soap figurines to notice.

After that, Twilight, Cosmo, and Wanda were at the design room where Rarity was making the dresses when Twilight began ranting, “Oh, you should have seen how she acted back there. I don't know when she changed, but she changed!”

“Well… she probably could’ve just been trying to spare Applejack’s feelings.” Wanda defended with a weak grin.

“Oh but you should’ve seen her,” Cosmo rolled his eyes before speaking in a high pitched voice, “Please call me Princess Mi Amore Cadenza.”

"Did I hear somepony mention my name?" Princess Cadence asked, almost as if she knew she was being talked about as she showed up with her bridesmaids, a green, white, and blue mare.

Rarity immediately bowed and began speaking, “Your highness! Let me just start by saying what an honor it is to play a role in such a momentous occasion.”

“Uh-huh, is my dress ready?” Cadence asked unenthusiastically.

“Yes, of course. Um, I've been working on it ever since I was given the assignment, and I think you'll be pleased with the results! Mmm!” Rarity stammered nervously before showing Cadence the white dress.

“I was hoping for something with more beading and a longer train.” Cadence replied snootily.

“Oh, right away.” Rarity wrote down in her notes.

Cadence then turned to the bridesmaid dresses, “And those should be a different color?”

“I think they’re lovely.” One bridesmaid spoke happily before a sharp glare from Cadence shut her up.

“Make them a different color immediately.” Cadence said with an ice cold glare to Rarity before leaving with her bridesmaids.

“Gee, maybe her name should be Princess Demandy-Pants.” Twilight snidely remarked to Cosmo, Wanda, and Rarity but only the fairies were listening.

After Luna and Celestia switched guard patrols, Twilight had shown up to the outdoor table with the rest of her friends sitting down and chatting before Twilight butted in, “Bet I can guess what you're all thinking. Cadence is the absolute worst bride-to-be ever.”

The five ponies and Timmy all looked shocked at this accusation but Spike pulled out the Cadence soap figure, “Who? Me?”

“Spike, that goes on the cake.” Wanda rolled her eyes causing Spike to chuckle nervously.

“Twilight, whatever are you talking about? Cadence is an absolute gem.” Rarity replied happily.

“Rarity, she was so demanding.” Twilight reminded the fashionista.

“Well of course she was. Why shouldn't she expect the very best on her wedding day?“ Rarity asked happily.

“I never acted like that when I got married though.” Wanda admitted to the fashionista.

“Are you sure? You are kinda naggy at times.” Cosmo raised an eyebrow but he shrunk back at Wanda’s glare.

“Applejack, did you know that after she told you how much she just 'love-love-loved' your hors d'eouvres, she threw them in the trash?” Twilight asked incredulously.

“Aw, she was probably just trying to spare my feelings.” Applejack smiled softly.

“No, she was being fake, and totally insincere.” Twilight scoffed, “Pinkie Pie, you must have noticed how she insulted…”

However, Pinkie and Spike were too busy playing with the soap figurines to pay any attention.

“Never mind, Rainbow Dash, you're with me, right?” Twilight asked hopefully.

“Sorry, Twi. Been too busy prepping for my sonic rainboom to pay much attention to the bride's bad attitude.” Rainbow Dash admitted uncaringly.

“The princess is about to get married. I'm sure any negative behavior she might be displaying is simply the result of nerves.” Rarity said calmly.

“And I'm sure it's the result of her changing for the worst and undeserving to marry Shining Armor.” Twilight snapped.

“Don’t you think you’re being a bit possessive of your brother?” Applejack asked uncomfortably with the rest of the ponies, Timmy, and Spike murmuring their agreements.

“Uh… I hate to play devil’s advocate but Twilight could be right here.” Wanda admits nervously.

“Yeah, Cadence didn’t seem stressed at all. She just seemed super cranky and mean.” Cosmo nodded along.

I am not being possessive, and I am not taking it out on Cadance! You're all just too caught up in your wedding planning to notice that maybe there shouldn't even be a wedding!” Twilight said angrily before running off leaving an awkward atmosphere at the table.

“We’ll go check on her.” Wanda told the others nervously before ushering Cosmo to float along with her.

“Whoa. Talk about a messy family drama.” Cosmo shook his head as he and Wanda floated along to find Twilight.

“I’m a bit worried about Twilight. What if she’s right about Cadence changing for the worst, Shining Armor could be signing himself up for an abusive relationship.” Wanda said worriedly.

“Shining Armor’s fine. Cadence can’t possibly be too bad.” Cosmo tried reassuring his wife calmly before Twilight sped right past them, knocking the two fairies over to the ground which she noticed and immediately gained an apologetic look.

“Oh sorry Cosmo and Wanda, I just need to tell my friends something urgent.” Twilight began speaking frantically.

“Oh boy, she’s freaking out again.” Cosmo sighed forlorn.

“What is it sweetie?” Wanda asked comfortingly.

“I just saw Cadence zap Shining Armor with a spell that made his eyes go all loopy. I tried to tell my friends but they wouldn’t listen.” Twilight said fearfully as she began tearing up, “I-I think he might be getting brainwashed. I’m so scared for him guys. This isn’t the Cadence I know.”

Cosmo and Wanda were shocked at hearing this information, not only was Cadence bossy and rude, but now she was casting spells on Shining Armor. This was only getting worse and worse. But something in Wanda seemed to click.

“Twilight… do you know of any shapeshifting magic?” Wanda asked curiously.

“Yeah. I’ve mastered transfiguration spells before. Why?” Twilight said, clearly confused.

“Well maybe Cadence is acting weird because that isn’t the real Cadence. It could be an impostor.” Wanda explained.

“…You’re right.” Twilight said in realization, “Cadence would never act like this at all. An impostor is the only explanation. I have to warn my friends.”

“No, that won’t help.” Wanda told the unicorn, “At least not completely, we need to go get Celestia. We should go talk to Luna that we need to see her immediately.”

“What about Timmy?!” Cosmo asked fearfully.

“He’ll be fine for now. I doubt the impostor is targeting him.” Wanda reassured her husband before she used her wand to teleport herself, Cosmo, and Twilight away.

Princess Celestia was surprised to be woken from her sleep so abruptly but after seeing Twilight, Cosmo, and Wanda at her bedroom door, she was wide awake and ready to hear what they needed.

Twilight told Celestia everything about the events of today, Cadence’s rude attitude, her bossiness, and even the spell she had placed on Shining Armor with Wanda explaining how she and Cosmo saw these events take place, all while Celestia listened carefully and once Twilight was done, Celestia finally spoke.

“Well Twilight… you have been right before about these things and after the events with Discord, I realize that not even I can predict every threat Equestria has to offer.” Celestia sighed forlorn.

"You really believe that an impostor took Princess Cadence's place?" Twilight asked her mentor with dread.

“As much I wish it wasn’t true. It feels like it is the only possible explanation.” Celestia sighed sadly, “We must postpone the royal wedding. Any plans the impostor is carrying out must be stopped at once.”

“But we don’t know where they’ve hidden the real Princess Cadence.” Twilight reminded her mentor, “They think they fooled everypony, but they can’t fool me. I’ll make her talk.”

“Twilight, I cannot let you do that. I cannot continue to let you risk your safety.” Celestia objected firmly.

“The impostor obviously sees me as a threat, it’s been antagonizing me since I got here. If they want me, then I have to step up.” Twilight explained, “Once we know where Cadence is, we can continue the wedding. We can’t cause a panic.”

Celestia sighed sadly, “Very well Twilight, but I must ask you remain careful.”

Twilight nodded and then walked out of Celestia’s room with Cosmo and Wanda floating after her.

“So when are we gonna confront this impostor?” Cosmo asked curiously to which Twilight gave the fairies an awkward look.

“Ooh, that’s the thing. Neither of you two are gonna be in the room.” Twilight said awkwardly.

“What?!” Cosmo and Wanda gasped in shock.

“You need to keep Timmy safe. This is my fight, and I need to do this myself. The real Cadence and Shining Armor are counting on me.” Twilight explained sternly.

Cosmo and Wanda looked at each other nervously, unsure whether to trust Twilight or not.

Princess Cadence did not suspect anything when she was called down to the throne room. Things were going perfectly so far, the wedding was coming out to be just as she hoped it would. There was no reason for her to worry.

However, when the doors suddenly closed on her, she found herself face to face with a furious Twilight.

“Twilight, I was just looking for you actually. Look, I know we’ve gotten on the wrong hoof but-“ Cadence began before Twilight stopped her.

“I don’t believe you. I don’t even believe you’re the real Cadence.” Twilight narrowed her eyes hatefully much to Cadence’s shock before Twilight smirked, “But that’s just it, you aren’t Cadence are you? It's clear you don't know anything about her personality at all. You may have been able to fool everypony else by using this wedding as a cover, but you don't fool me!"

“Tw-Twilight, how could you say such a thing? I am the real Cadence, I promise.” Cadence began to start crying but it didn’t fool Twilight one bit.

“That’s not gonna work on me. I know you’re somepony evil.” Twilight narrowed her eyes even more at the pathetic display as she flared her horn, “Now tell me, where have you hidden the real Princess Cadence and what are you planning with Shining Armor?”

Rather than confess like Twilight was hoping, Cadence gave Twilight an ominous glare, much to her shock and worry, “You want to know where Cadence is, huh? How about I show you myself.”

Suddenly, green flames began to swarm Twilight and a forcefield formed around her, she tried teleporting out but it was no use, she still remained defiant however.

“You won’t get away with this, my friends will know I’m missing. They’ll-“ Twilight began ranting before Cadence evilly laughed.

“And where are those so-called friends now? They’ve been putty in my hoof for a long time now, and if they cared so much about you, they would be here.” Cadence smirked at Twilight as she descended into the flames.

Twilight could only stare in horror, she had thought that confronting the impostor alone would save the day, but all it did was make things worse.

This was all her fault.

But Little did she know, disguised as flowers, the two fairies witnessed the whole thing.