"But… but…" Twilight stuttered. "Don't any of you believe me?" She looked pleadingly around at the rest of the Elements. "Not one?"
"Of course not!" Trixie said, loudly. "Trixie could not possibly believe that Mi Amore Cadenza, who congratulated her so after her award-winning performance at the school play the first year she knew Twilight, could be evil!"
Twilight blinked, despair giving way to confusion. "But-"
"Silence!" Trixie turned her nose up. "Trixie will hear no more of your lies. Good day."
The azure mare flounced off.
"See, dear?" Rarity said. "You're the only one who's confused. I understand, it's hard, because you feel like she's taking your brother away, but-"
An anvil came flying in through the window and smacked into a rippling green shield about two inches short of Cadence's face.
Trixie reappeared in a puff of smoke, enveloped in a shield. "On the other hoof, this is clearly NOT Mi Amore Cadenza."
"What makes you think that?" Dash asked, over the general hubbub of shock and confusion.
"Trixie's performance was not award winning in the slightest. She managed three words, was overcome with stage fright, and teleported herself, half the floor and every other costume on stage into the basement. It was a disaster. But Cadence laughed her mane off when she was told, and it still makes her giggle at the merest mention."
Trixie shrugged. "Besides, her magic colour is green. Is Trixie the only observant one here?"
A bolt of green lightning two inches thick smashed into Trixie's shield, shattered it, and drove her into Applejack and Rainbow Dash. All three ended up in a heap on the floor at the other end of the room.
Trixie's hoof stuck up out of the pile. "Trixie considers this vindication! Also ow."
Shining Armour galloped in. "What's going on? Dear? Why are half the Elements of Harmony in a heap on the floor?"
"Forty-three percent!" Trixie corrected.
"And why do I suspect it was your fault, Trixie?"
"Experience?" Twilight muttered.
Rarity ignored the byplay. "Since when did Cadence have green magic, Sir Armour?"
"Green?" Shining said, frowning. Come to think of it, the last few times she'd cast a spell, it had been with a green overglow. But... the spells were cast with her normal colour.
But it was green.
But... normal colour...
"Oh, do you have another headache, dear?" Cadence said, advancing.
Twilight moved to block her. "Whoever you really are, you're not touching my brother."
"Trixie would suggest that next time you attempt to confront somepony, you do it in front of someone at least as powerful as them." Trixie had finally disentangled herself from the pile of pony up against the wall, and cantered up to her friend's side. "Twenty-three."
Twilight nodded. A single shield built, encompassing both of them, and made of mingled magic. Trixie's number code indicated the way they were to interleave their magics, resulting (hopefully) in something far more powerful than one alone. "Pinkie, see if you can sort out whatever's happened to my brother."
"Trixie thinks it is because you don't make sense."
"That makes sense!" Pinkie said cheerfully, then frowned. "Which would mean it doesn't. Hmmm..."
The false-Cadence and both powerful unicorns faced one another down in a standoff, looking for tiny cues that would indicate weakness. Twilight and Trixie alone were powerful, and working together their strength was – not enough to match an alicorn, perhaps, but possibly enough to resist one if they stood wholly on the defensive. If 'Cadence' made a move, then the question would be settled, and neither side was confident enough to-
Applejack sighed. "Why is it ah have to be the smart one sometimes. RD, go fetch the Princesses."
A rainbow blur shot out of the room, flying at about two feet above head height and causing everything in the room to flutter about in the wind.
'Cadence' snarled slightly. Now she was under a time limit. She'd have to smooth all this over quickly, and hitting the minds of all those present would be difficult.
No other options were left.
Dropping her disguise, the Changeling queen slammed forward with a bolt of power representing about three years' life energy. The two Magic bearers' shield warped and fluttered like a sail in a high wind, but held.
However, three of the four guards watching the standoff also dropped shapeshifts, knocked the last one out and lunged for the remaining ponies.
The duo's magic-polarized shield fell when Twilight was kicked unceremoniously in the head by a Changeling, and Trixie went down less than a second later to a stun spell that probably could have kept a Hydra unconscious for a week.
Chrysalis inhaled deeply to offset the effort of channeling through so much mana, and looked around. Things were mostly under control. The unconscious guard was being dragged into a corner for dealing with later, and even the annoying pink pony was held in the air by the other two of her Changelings. She took over control of the magic surrounding Pinkie, and hit her with another stun spell on top of that.
"Have you any idea how annoying this is?" Chrysalis asked, her voice trembling slightly. "I was so close to sorting it all out, and you... infuriating ponies have to nearly spoil everything. I wonder why Cadence never told me about the light blue one..." The queen snorted. "Probably thought to trip me up. Well, I'll send you both down there to join her."
She turned to the guards. "Two of you, replace the purple and light blue unicorns. You." The third one was indicated, as his fellows began to change. "Get the real unicorn guard out of here – carry him down to the infirmary in your guard disguise. I will be down to change his memory as soon as I have smoothed things over here."
"What is the cover story?" Twilight's voice asked from the changeling adopting her form.
"Twilight Sparkle and Trixie were both convinced that there was something wrong with Cadence, and acted with extreme force without listening to reason. I dissipated their anger, reminding them of their friendship with me, and now they are fine."
"Understood." Trixie's double said.
Chrysalis' horn flared green, and the original unicorns vanished in a swirl of sparks.
"Now. Lift all of the others, so they can see me. I want this story consistent." Chrysalis began to mentally prepare her memory-alteration spell. The episode with Shining Armour nearly breaking free had at least shown she'd done it well enough with him – a potentially very dangerous unicorn being paralyzed by contradictory thoughts was enough for her to be working with.
Twilight awoke in near darkness. "Uh... what happened?"
Fighting down an irrational wave of panic, Twilight lit her horn with a simple light spell.
...well, that explained how comfortable she felt. She'd landed on Trixie. And, for whatever reason, the other pony was not responding in any way.
"Trixie? Are you alright?" Twilight asked, rolling off her and getting up.
Trixie was silent. She was breathing, the long and slow breaths of the deeply asleep.
"Right, how did I used to handle this..." Twilight cast her memory back to days when both of them had had early lectures. "Ah, right."
Her horn flickered slightly as she cast a spell - the hyperbolic amplification.
The room – cave – they were in shook slightly. Small rock particles bounced on the floor, driven by the force of Twilight's sudden mimicry of the Royal Canterlot Voice.
Trixie bolted upright, driven by the learned reflex of years. "Trixie is up, Twilight, you can stop... wait. This isn't our rooms."
"No." Twilight agreed grimly. "I think we were sent underground by whoever or whatever that was replacing Cadence."
"Right." Trixie said, forcefully. "Let us show her who she was dealing with."
"I think she already knows." Twilight said, deadpan. "She smashed your best shield, nearly blew through our joint one and then something hit me on the back of the head."
"Not what Trixie meant." The azure unicorn concentrated... then did a double take at her back, at the floor, and behind Twilight just in case. "That fiend! She has stolen my robe and wizard hat!"
"I thought the term was 'mage'?"
"Irrelevant! What is relevant is that that was where most of Trixie's useful equipment was. Like, say, all the paper we could have used to warn everypony what was going on, via Spike."
"Don't they already know?" Twilight asked, vaguely. "I mean, Rainbow did-"
"Consider the following. This unknown being is capable of changing her shape. She is also possessed of allies, who were infiltrated into the castle – less time was taken for them to arrive than for the Hummingbird to fetch Princess Bright light and Princess Night light, so-"
"I really wish you'd stop calling them that-"
"-so therefore it is at least possible that the allies can shapeshift as well. Why remove us from the picture, if not because they were planning on imitating us? The lack of yourself might be explained away due to a sulk, but Trixie herself has no particular attachment to your brother and would openly be planning on starting a pie fight at the wedding."
Twilight gave up. "Tell you what, keep talking and I'll see if the conclusions are any use to us."
"Now, they did not remove all involved from the room, just us. This we know because we arrived together and any others would as well."
"Okay, I'm going to interrupt. How do you know that?"
"Dust. There are three exits, and not one of them has the dust disturbed upon the floor itself – there is merely a new layer from your shout settling onto it. And if we were to be split up, the powerful mages capable of synchronization would be placed in different groups. Now, this means there must be some way to render the yokel, the doormat, the neon sign and your brother unable to explain."
"I don't follow the first part, but I'll grant you the second." Twilight said, running thought her list of divinatory spells. Once she had a position and depth, she could know if a teleport was possible.
"In addition, Shining Armour had noticed nothing unusual about this entity before now. In light of your accusations, Trixie suspects mind magic – and in that case it is lucky for the entity that she placed us down here."
"Why?" Twilight asked, frowning. "Why us specifically? If she can get to Shining..."
"Trixie has some powerful failsafes around her mind, after what happened last time." Trixie looked down for a moment, before her head snapped round to one of the entrances. "Who goes there?"
"Trixie?" Came a weak voice.
"Nooo... Trixie is here." Trixie answered slowly. "She will ask again. Who goes there?"
"It's me, Trixie, Twilight - Princess mi Amore Cadenza."
"Cast a spell." Trixie snapped.
"Pardon?" both the other ponies asked in unison.
"Cast a spell right now." Trixie's horn began to glow as she built a lightning spell.
Cadence quickly cast a weak light spell, illuminating her more fully – and Trixie let hers dissipate.
"Good. Your magical colour is normal."
"I don't understand – and why are you two here? Did you run into Chrysalis as well? But you'd only be in Canterlot for... the wedding." Cadence' face fell. "Has it been that long already?"
"Chrysalis..." Trixie rolled the name around on her tongue. "Interesting. Now, both Trixie and Twilight worked out that you had been replaced rather quickly, but we think this Chrysalis has been brainwashing Shining Armour. And it may be that... she?" Cadence nodded. "Has managed to smooth over our accusations."
Princess Celestia came into the room at a canter, stopping on seeing not the standoff Rainbow had described but a relatively amicable eight ponies talking in small groups.
"What was going on? From what Rainbow Dash said to me, there was about to be a fight!"
"No, it's all our fault." Twilight said, looking ashamed. "I was worried about how Cadence was going to take Shiny away, and Trixie got overexcited again-"
"She did not!" Trixie interrupted. "She merely paid what appeared – at the time – to be appropriate caution."
"And we nearly did something stupid, but Cadence managed to stop us."
"Well, then, my students, it seems you have-" Celestia stopped, suddenly struck by a sense of wrongness. "There is something not quite right. Has Trixie done something reckless again?"
"No." Shining Armour said, shaking his head sadly. "My prospective wife was replaced some time ago by a brainwashing, insectile invader whose cohorts have replaced Trixie and my sister."
Several jaws dropped – most notably on 'Cadence' herself. "What? Shiny, don't tell me you were-"
Shining Armour raised his head proudly. "I, you lying daughter of an eohippus, am Shining Armour, Knight-Captain of the royal guards, and expert in all kinds of magical shields and barrier spells. You use direct eye contact to hypnotize ponies, and you can't do it when there's an opaque magical barrier across their pupils."
"You blinded yourself?" 'Cadence' asked, shocked.
"An officer has to make many sacrifices." Shining said blandly. "Besides, it's temporary. More importantly... where did you send my sister and her best friend?"
The faux-alicorn's eyes flicked downwards for a fraction of a second. Shining of course did not spot it, but Celestia did. "I see. The old mines."
"I had hoped to delay this." 'Cadence' said, and slammed forwards with even more power than she'd thrown at Twilight and Trixie. Ponies and Changelings alike dove for cover as Celestia replied with a beam of her own, which met the reverting Queen's beam head-on and held it... though it slowly, gradually, began to crawl back towards Equestria's elder ruler.
Pinkie's tail twitched... sideways. "Everypony down!"
A kaleidoscope of light and sound erupted through the stonework and out again on the same side of the room, taking off most of that outside wall, as Rainbow Dash returned in style. Less than a second later, Princess Luna in full barding hit the Changeling Queen with the force of a small meteorite.
Dash ended her Rainboom, looped around again and landed on the floor. "Hey, everypony. AJ, you said 'Princesses', right? As in, plural?"
"That ah did." AJ tipped her hat. "Good work."
Shining Armour trotted over to the hole in the wall and looked out. "Good to see you, miss Dash. And, more importantly, hear you – best proof that Cadence' replacement wasn't trying to trick me any more. Hm, that can't be usual."
"Huge horde of insecty things like those fake guard, hovering outside the shield. So that's what they were planning..." Shining winced. "The shield's not going to hold terribly long if I have to keep it up against this sort of attack."
"Er..." Fluttershy's voice was quiet as usual, but the sudden absence of the loud sounds of combat meant it was heard easily. "Why are they attacking in the first place?"
"We need love." Twilight's doppelganger answered promptly. "Feed off it, live off it. Our queen's plan would have given us all the love we needed."
"But why not just ask?" Fluttershy continued. "I love all kinds of things. Mainly animals, but if someone's hurt, or in trouble, or... just... there, really... I care for them."
"Unless a Minotaur's spoken to her recently." Dash clarified.
"That's not helping." Rarity said quietly.
"You... do." The changeling said, wonderingly. "How? Why would you give your energy to one who tried to harm you?"
"Love doesn't cost anything, silly!" Pinkie said, bouncing over. "It's because of how it's a positive, runaway reaction that consumes no reactants!"
She looked around at a dozen blank faces. "Fine, then. Because it's something where by giving it away you get more of it! Like measles? No, that's worse... Hmmm..."
"Pinkie, are y' plannin' a musical number again?"
The pink earth pony tried to hide a musical stand and sheaf of notes behind her. "Nooo..." Everyone wondered where they'd come from in the first place, then shrugged it off.
"Actually, I had one all ready." Chrysalis said, from where the Royal Sisters were keeping her at horn-point. "I thought it was good – it has a lovely double meaning in it about how 'this is the day I longed for'."
"Ooh, sounds good!" Pinkie ruffled through several pages of musical notation. "Not bad, but you might want to get Cadence singing along for full impact. Cut the view between you and her to show off the double meaning."
Chrysalis blinked. "Are those my notes? I left those at home! Where did you get them?"
"It's Pinkie." chorused every other pony in the room. For them, the explanation was sufficient.
"Alright, then." Chrysalis said a moment later, aceeding to Celestia's suggestion. "I'll do that."
Chrysalis slowly trotted over to the window, covered by both alicorns the whole way, and connected her mind to the swarm. Her voice rolled out, full of power and authority.
"STAND DOWN. INVASION CALLED OFF."
Several hundred ponies throughout Canterlot looked vaguely disappointed, then transformed into Changelings and took to the air.
"Not terribly poorly planned." Luna commented. "Good infiltration measures. Though I question your expenditure of so much power to handle just one of us."
"...are you talking shop with me?" Chrysalis asked, incredulous.
"This is Equestria. We have a good track record for making enemies friendly. Besides, you did better than me."
"There." Twilight said, firmly. "That's the way out."
"Trixie thinks it is very high." The azure unicorn said. "And she also thinks that a location spell which actually gave our location would be better."
"Oh, shush. Besides, I've been more concerned with..." Twilight ran over the last year and change in her head. "Every other type of spell that's not dark magic."
Trixie shrugged, no mean feat for a unicorn. "She will see you at the top." A bamf of smoke replaced her, and she waved from the mine entrance.
"I didn't know she could teleport that far." Cadence said. "She must have been practicing."
"We've both had a lot of practice recently." Twilight said. "You know I can teleport at least as far as Ponyville now?"
"Most impressive." Cadence agreed. "Now, I'm afraid I'll have to get a bit of a run up, I'm not exactly in peak condition for takeoff. Would you mind..?"
"Oh, sorry." Twilight joined Trixie to clear the takeoff area, and set about unlocking the door to the mine.
"Psh." Trixie said after not more than a couple of seconds. "Let Trixie show you how it is done."
Twilight stood back, letting her friend work on it.
A moment passed in stillness...
"Hm. It would appear that Trixie is out of ideas when she does not have access to her equipment."
"And what were you planning if you did have access to said equipment?"
"Trixie!" Twilight half-shouted. "We don't want to bring down the entire roof!"
"Second option would be a crowbar." Trixie rolled her neck. "Third would be a screwdriver, and fourth would be-"
"Wait!" Twilight said excitedly. "An explosion is basically something burning fast - a fast chemical reaction, right? I mean, for stuff you used before the extract."
"Indeed." Trixie nodded. "That is basic."
"I've seen you make paper explode before. Do you have a reaction accelerating spell?" Twilight pressed.
"Then rust the hinges off!"
"...Trixie will allow that that is a good plan." Putting action to words, Trixie cast the spell. Twilight copied it, and within a few seconds the heavy-duty doors collapsed with a juddering BOOM.
Cadence alighted on the landing behind them. "Good work, you two. Now, let's make sure we arrive in time."
"Trixie has always wanted to be the one who objects at a wedding."
"Didn't you do that when our professor of mathematics got married?" Twilight asked.
"Indeed she did." Trixie allowed. "But this time it shall be justified."
"Trixie feels cheated."
"At least everything worked out okay." Twilight tried.
"Hello, Trixie, Twilight!" Rarity said, noticing them. "I'll get the others, do keep that table for us. Oh, this is Pupilla – she's expressed interest in a modelling career with Photo Finish and I!"
The alabaster unicorn swept off, somehow leaving the Changeling that had been following her behind at their table in a way that seemed entirely natural.
"So." Trixie said after a few uncomfortable seconds. "Trixie understands that your race are empaths?"
"Yes." The Changeling's current form wasn't quite a pony, and wasn't quite her base form. A featureless unicorn with a jet black coat and no cutie mark, it looked unusual – but less immediately startling than a Changeling naturally did.
"Does that make things easier?"
"You would think so." Pupilla replied. "But because only the Queen has a voice in her natural form, it makes it harder to actually understand things."
"The Queen of a Changeling hive was originally an adaptation to communicate with outsiders on their terms." Pupilla explained, warming to her subject with every appearance of enthusiasm.
It is enthusiasm, Twilight. The lavender unicorn told herself firmly. Just because they feed on emotions doesn't mean they don't feel them themselves.
"Trixie thinks she sees. So because your main form of communication is empathic, your opinion on the plan was based primarily on how strongly Chrysalis felt about it."
"Exactly. And we deferred to her as the expert." Pupilla gave a shrug. "But in any case, that's over now. The example of Luna gives many of us hope."
"Shouldn't that be 'Princess Luna'?" Twilight asked.
"She's not my princess – yet, at least, that depends on the diplomacy – and Queen Chrysalis isn't your queen." Pupilla said.
"Trixie thinks she has you there."
"Hi!" Pinkie said, materializing at the table. "Oh, you're the changeling that Rarity mentioned! Hello, I'm Pinkie, and if you're going to live in Ponyville then I'll have to throw you a party for it after the big super-party for stopping a war and all of Equestria getting a new friend!"
"...Did you know," Pupilla said distractedly, "That your emotions taste like more sugar than is probably safe?"
"There's a surprise." Trixie and Twilight chorused.
Dash arrived next, and promptly began alternating between demanding details of what she'd missed and gushing about the bits the unicorns had missed. "Oh, I wish you'd been there to see it, Trix! I blew a whole wall out of that room, and then Luna went in at nearly Rainboom speeds! It was awesome!"
"You are talking about my monarch here." Pupilla said, with a hint of rebuke.
"And Trix here blinded Princess Luna and practically blew her up before we used the Elements on her." Dash shrugged. "It's just how it works – if you don't have the Elements ready, either you beat 'em up until you do or beat 'em up until they start listening to reason."
"Um... it's because of stress hormones." Fluttershy said softly, sitting down herself. "Somepony isn't likely to listen because they're still in battle mode. It's why I got my black belt."
"Yeah." Dash nodded, then noticed everyone else looking startled. "What? She does chiropractory for bears."
Rarity and Applejack arrived together, because the fashion designer didn't have anyone else to reach.
The farmer nodded as she sat down. "Good t' see you two, Trixie, Twilight. Hope you ain't the worse for wear."
"No, we're fine."
"Trixie is disappointed she did not get to say she objected at a wedding. And mean it."
"Ah'm going to go ahead and take Twilight's answer instead." AJ said amicably.
"So, I see you've been getting along fairly well with my friends." Rarity said to Pupilla.
"Enough to be going on with, I think. So!" Rarity looked over at Dash. "Did you get the news?"
"What news?" Dash looked wary.
"Well, if you don't know..."
"Just tell me already, Rarity!"
"Fine. You, dear, were asked for to conclude the flyby. By name."
"Really?" Dash's face lit up. "You're not joking, are you?"
"Well, I could be mistaken, but Spitfire did mention how there was really only one pegasus to ask about a sonic rainboom."
Rarity slid a small piece of paper over to the stunned pegasus. "I believe this details where you are to meet them for planning. Do hurry, they shall be taking off soon."
Dash left the table straight up and curved like a seeker spell towards the indicated location, and most of the ponies around the table laughed.
"What's the problem, Trixie?" Twilight asked, noticing that she hadn't joined in.
"Eunni." Trixie said succintly. "Trixie feels like she did not accomplish anything noteworthy."
"I know what would help!" Pinkie said, rummaging improbably in her mane. "You see, I had a talk with Cadence when I set up the band, and she requested informality."
"Ta-da!" Pinkie pulled what she was looking for out.
A custard pie.
"I carry it everywhere in case of clown themed emergency." She winked.
Trixie looked from the pie, to the pony called Pie, and back again. Then, slowly and deliberately, she lifted the confection in her magic.
"Trixie will be right back. Probably at high speed, being chased by an enraged alicorn and her husband."
AN: To make this work, I had to have Twilight not confront disguised Chrysalis in front of Celestia. But the idea of confronting her in front of all (the other) Elements of Magic seems to make sense.
This is interesting, in that I wrote it while thinking about how a lot of the characters would react to changing situations - in particular, how would Shining use his "barrier warrior" type magic to defend against mind alteration if he knew it was coming, and in what stages would Chrysalis resort to violence over deceit.
Oh, and "daughter of an eohippus" would be somewhere between calling someone an unevolved monkey and calling them an S.O.B - the eohippus, more properly called the Hyracotherium due to a quirk of the taxonomic system, is the early cenozoic ancestor of all horses.