So... Where the buck do I start? I was walking through the hallways of the castle and had just realised that I had no idea where to start the investigation. Hmm... If I was right about the shapeshifter having to cast an anti-detection spell to ensure that they're hidden, then it would either have to be very powerful or very specific. If it's powerful, and they don't have access to a lot of magical energy, then they would have to keep applying it after a certain amount of time. This would mean that there's likely a large amount of excess magic radiation where the spell was cast. I might be able to trace it back to the caster if I can find it.

On the other hoof, it could be a very specific anti-detection spell. If that's the case then it would most likely be masking the shapeshifting as something else, meaning that I could search for a build up of one kind of spell centered around a single Pony. What if they were using a rune carved into a necklace or something similar? It would still have to be periodically charged.

The most likely option for them is a big powerful spell, which is especially good since it's so convenient for me. Okay. Time to search for magic radiation. I cast a high strength but low range general magic detection spell and continued my wanderings through the hallway.

Applejack was running around the kitchen while Twilight sat in a heap checking things off of a list. I wasn't paying much attention to them, I was more interested in watching the other bakers and chefs. The shapeshifter might be hiding here, trying to poison the food... Or just hiding here in general. Either way, if they are, they'll probably be less skilled in the kitchen than the others.

Suddenly the doors slammed open and Miyamoto came marching through the kitchen.

"Hiya, Princess!" Exclaimed Applejack as everypony other than Twilight and I bowed.

"Please, call me Princess Mi Amore Cadenza," Miyamoto declared snobbishly.

"Hiya, Princess Mi Amore Cadenzyme!" God-Horse III growled.

"Apps, it's Miyamoto Cadenzyme," I said from the other end of the room.

"Oh. Than's, Vesper. Hiya, Princess Miyamo'o Cadenzyme!"

"It's not-! Oh, forget it," snarled Miyamoto.

"Ya 'ome t' che' ou' wha's on 'he menu for your bi' 'ay?"

"What?"

"Ah sai'; 'ave ya 'ome t' che' ou' wha's on 'he menu for your bi' 'ay?" Is it me or has Applejack's accent been getting thicker lately? Nah, it must be just me.

"Uh... Yes?" Applejack hoofed her a plate of apple cakes. Miyamoto took one and bit into it. She immediately retched and was forced to put a hoof to her mouth to stop herself from spitting it out. Applejack hadn't noticed yet, so Miyamoto forced herself to swallow. Her face went a bit green. "They're, uh, delicious..." She managed to say before retching again. "I... Love, love, love them?"

"Aw, shu's!" She pulled out a paper bag. "Whah don' ya ta'e a few t' ger? I know how ya bri'es can be; so buseh, you forge' to ge' a li'le some'in' in yer burlleh!" Miyamoto took the bag and, as soon as Applejack's back was turned, threw it in the trash. She ran out the doors and slammed them behind her.

Hmm... Nopony's acting weird or out of character so far...

I'd found the excess magic radiation in a random closet. I wasn't able to trace it back to the caster, but I was able to do a few tests on it.

It was clear that the spell was being cast on the same Pony casting it, meaning that there was probably only a single intruder. This was good for me; it meant that the shapeshifter had to be a Unicorn or an Alicorn. While they would have to be powerful, they might be boosting their power with runes and recharging them with magic from whoever they were replacing. Well, that's if whoever they're replacing is still alive. With how quickly the spell seemed to be cast, the shifter would have to be inside or around the general vicinity of the castle.

There was a lot of excess radiation in the closet, so it was probably one of the few places they frequently cast the spell. I need to get somepony to watch this hallway. I'll probably get a guard to- Wait, what happened to Watcher?

"Sir, you need to get off now. This is the last stop."

"Ugh... Wait, why am I on a train? Why am I in Manehatten?!"

"Sir, leave the train before we have to take things further!"

"W-Wait! There's been some kind of mistake!"

"You brought me to this!"

Whoosh!

Thud!

"Argh!"

I'm sure he's fine. Anyway, Celestia's hopefully told the guards that I have some authority or something, otherwise I'll have to get her to assign me a couple. While the hallway is being watched, I can see if I can find anymore radiation trails.

"Oh, you should have seen how she acted back there," moaned Twilight as she paced back and forth through the room. We had moved onto Rarity and Twilight wouldn't shut up about Miyamoto. "I don't know when she changed, but she changed!" Twilight put on a mocking voice, "please, call me Princess Mi Amore Cadenza!"

"Did I hear someone say my name correctly?" Asked Miyamoto Cadenzyme herself, walking into the room with three random mares. Wait, why did she say someone instead of somepony? Does she not realise that there are only Ponies here? Well, whatever. Probably just habit. But wait, God-Horse I doesn't have that habit and she's been around for much longer... I narrowed my eyes. Maybe I should be keeping a closer eye on her... I started paying attention again and saw that Miyamoto was looking at a dress with Rarity.

"I've been working on it ever since I was given the assignment," explained Rarity, "and I think you'll be pleased with the results!" She grinned. Miyamoto gave a look of disgust.

"I was hoping for something with more beading and a longer train." Rarity looked surprised before grabbing a notebook to write down what Miyamoto had said.

"Oh, yes, of course." Miyamoto took a glance at some other dresses.

"And those should be a different colour."

"I think they're lovely!" Exclaimed one of the random mares standing in the doorway.

"Me too!" Agreed another.

"I love them!" Finished the third. Miyamoto glared at them.

"Make them a different colour," she repeated before she marched out of the room snobbishly.

"Gee," growled Twilight, "maybe her name should be 'Princess Demandy Pants'."

After a day full of checking up on everypony (and being followed by Princess Miyamoto 'Demandy Pants' Cadenzyme), the ten of us- Wait, where's my bitch?

"Oi, mate! Ya need some bloody wonga if ya wanna stay 'ere!"

"P-Please! I just need somewhere to stay until tomorrow so I can finish flying to Canterlot and then my friends-!"

"Didja 'ere tha', baws? Diss here Pony boy dinks his fwends can 'elp 'im!"

"I thinks we oughtta show 'im some fwends of our own!"

Scrape!

"N-No! Not shovels! ANYTHING BUT SHOVELS!"

Thwack!

"ARGH!"

Oh well, he'll turn up eventually. The nine of us, minus Twilight, were sitting around a table outside of a restaurant, waiting for our orders to arrive. Dad looked deep in thought as he sipped at his cider. Twilight came out of the restaurant with a drink and sat down at the table.

"Bet I can guess what you're all thinking," she claimed. "Cadance is the absolute worst bride-to-be ever." Everypony except me and Dad looked at her with a surprised or shocked expression. Dad didn't blink.

"To be fair," I said, "the husband's worse." Twilight opened her mouth to retort but soon closed it again.

"Yeah, okay, that's pretty fair."

"Twilight, Vesper," started Rarity, "whatever are you talking about? Cadance is an absolute gem!" I snorted.

"She's got a thicker skull than any Crystal Pony I've ever met," I muttered. Rarity looked confused.

"A what Pony?" Oh yeah, they aren't a thing yet...

"Future joke, you'll get it later." Dad suddenly sent me a psychic message. What colour was God-Horse III's magic aura? Green, why? I've tried complicated stuff so now I'm trying something simpler.

"Hey, Twilight?" Dad asked suddenly. "What's Cadenza's magic aura colour?" Twilight looked as confused as Rarity.

"Blue," she answered. "Why?" Dad slammed his head on the table making everypony else jump. I DID ALL OF THAT RADIATION SCANNING FOR NOTHING?! REALTA BUCKING DAMN IT! He stood up and stumbled towards the castle.

"I've got to go do something. I'll see you all tomorrow." He summoned a Support Circle and flew off. Well, that happened.

"I' soun's lah' Clah' 'rees wi' you," said Applejack. "Bu' Ah s'ill don' see wah you' be thin'in tha' in the firs' place."

"Applejack, did you know that after she told you how much she just 'love-love-loved' your food, she threw the bag you gave her in the trash?" Asked Twilight.

"Aw, she was 'ro'a'ly jus' 'ryin' to s'are my feelin's."

"She did raise her voice at one of my birds during rehearsal," murmured Fluttershy.

"See?! Rude!" Exclaimed Twilight.

"But he was singing really off key." She held up what I assumed to be the bird in question and let the bird make the sound of hacking up a lung. Twilight looked to Pinkie.

"Pinkie Pie, you had to have noticed how Cadance treated-!" Twilight stopped suddenly when she realised that Pinkie was messing around with dolls along with Spike. "Never mind. Rainbow Dash, you're with me, right?"

"Sorry, Twi. Been too busy prepping for my sonic rainboom to pay much attention to the bride's bad attitude." Twilight growled.

"Vesper?"

"Yep." Twilight looked surprised.

"You... You agree with me?!"

"Yeah, she's worse than Raindick." Twilight grinned.

"Finally! Somepony agrees with-!"

"But it is her wedding, so she kinda has the right to be as bitchy as she wants."

"Vesper's right, Twilight," said Rarity, "the Princess is about to get married. I'm sure any negative behavior she might be displaying is simply the result of nerves."

"That's not even slightly what I meant."

"Well I'm sure it's the result of being an awful Pony who doesn't deserve to even know Shining Armour, let alone marry him!" Shouted Twilight.

"Thin' may'e you're bei' jus' a 'iny 'i' 'ossessi'e of your 'rother?" Asked Applejack. Everypony except Twilight and I made sounds of agreement.

"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 at all!" They groaned in disagreement. Twilight groaned loudly, grabbed her drink with telekinesis and started walking away. "Buck this, I'm gonna work on my magitech!" Well, that happened.

Author's Notes:

Applejack must have all the accent!

---

"She's got a thicker skull than any Crystal Pony I've ever met,"

Alternate version of the line I decided not to use:

"She's certainly more dense than any Crystal Pony I've ever met,"