Mirrored Shield trotted smartly into the briefing room. "Reporting as ordered, captain, your Majesty."

"At ease." Shining Armour replied, glancing to his monarch, who nodded.

The disguised changeling let his legs and wings relax marginally, absently tasting the emotions of the other two ponies in the room. The captain felt exasperated, faintly, behind his professional demeanour. Apparently he trusted his liege to explain her behaviour. Said alicorn was mischievous/interested/expectant, with a side of concern.

"Now, Sergeant. Her Majesty tells me your unique talents make you especially suited to covert operations. I can't see it myself – you're perceptive, and a good NCO, but not exactly my first choice. I'm sure she'll explain herself later, though." Shining levitated up a map. "Manehattan. There's been some unusual reports from the area and the local law enforcement have asked for help – they say they can't handle it themselves. After reading their reports, I'm inclined to agree."

Shield spent a few minutes looking through the provided information, his heart sinking imperceptibly. It looked serious – fourteen missing persons in the last week, every one of them an earth pony. But just as problematic was that, between them, his liege and his commander were suggesting he'd have to reawaken his old powers once more.

"As you can see, something serious is brewing." Shining said, once the faux-pegasus had finished a first read. "It's not just coincidence, either – the last two to go missing were the Oranges. Sophisticated high society types with strong family traditions – no way they would just leave."

"I'm sure you're anxious to continue, captain." Celestia interjected calmly. "But I think now might be a good time to demonstrate the reason for my confidence. Don't you, Mirror?"

Accepting the implicit command, Mirrored Shield bowed his head and dropped his disguise.

To the captain's credit, he both got over his shock with alacrity and restrained his first violent impulse. "Changeling! What-"

"Stand down, Captain." Celestia said, the snap in her voice giving it authority. "Mirror is a loyal guard and a brave individual."

"If you say so, your Highness." Shining said, not taking his eyes off the changeling. "Where's the real Mirrored Shield?"

"It's me. I've been disguised since I was recruited." Mirror flicked his gossamer wings. "My 'negation of attacks' talent isn't an unusual variant of weather magic, it's just shapeshifting the damage away."

After another suspicious look, Shining turned away. "I'll trust your judgement, my princess. But why him specifically?"

The changeling returned to his disguise. "I have one idea already. My analysis is that whatever's causing them to go missing is either related to the ease of the initial capture, or to preventing them escaping again. In either case, I would be a way to insert a Guardsman in the guise of a normal earth pony, but with the abilities to escape – or seek help."

Flaring a white wing, Mirrored Shield began pacing. "I could perhaps create a relative of those higher-class ponies you mentioned, to explain my presence. If they're as cultured as that, then perhaps… yes, that might work. If I appear to be an estranged relative who heard about their disappearance, and sufficient of – well, of a brat – to demand an escort, then my entire squad could be brought along without making much of a ripple."

"Impressive." Celestia commented.

"My original purpose was infiltration for long periods of time. I have to know how to construct a cover identity. My main concern is that there's no supporting evidence for… Orange Chance, I think." As he spoke, his form washed over with green fire once more. Wings disappeared, his coat darkened to a burnt orange colour with yellow mane, and the mirrored shield on his flank changed to a pair of bright orange dice totalling seven.

Shining gave the new earth pony a look over. "You seem to have lost weight."

"I shrank muscles." 'Orange Chance' shrugged. "And I think his talent should be gambling. It's a common pastime of the idle rich in Canterlot, and my empathic ability might let me fake that one fairly well."

"How are your energy reserves?" Celestia asked. "I understand you supply yourself from the friendship shared amongst your squad."

"I do. And I have a few months." The Sergeant frowned. "It's been a while since I transformed so often, but I don't appear to be out of practice – it cost no more than usual."

"Useful." Celestia took a quill up with her magic, and began to write on a sheet of paper. "Do go on, I shalln't be a moment."

Orange Chance looked up, counting with his hoof. "Two… three… yes, that ought to do. I'll make sure to have something expensive on, a large carriage and a guard escort. Between them that should stop any pony from actually realizing that I'm a cipher." He winked, then schooled his expression into something haughty. "After all, I am of the Orange family, and as such deserve an escort as no more than my due."

Shining Armour chuckled despite himself. "Who did you base that attitude on?"

"Blueblood, who else?" Chance shuddered. "I was assigned to his detail once, and about the nicest thing I can say for his attitude is that he doesn't realize he's doing things that are rude."

"Sergeant?" Celestia said, finishing her writing with a flourish. "I have here a letter of marque for you, to keep on your person at all times. It identifies you as a changeling in my service and by my cognizance."

Chance took the letter, his hoof trembling slightly. There it was. Official recognition.

"…I'd better get things sorted out, then." He said, shifting back to Mirrored Shield. "I'll let the squad know I'll be dispatched to… let's say Stalliongrad, with an urgent message, and that they're to look after some noble blowhard headed for Manehattan."

The three of clubs came up on the river. With a smug smile, an orange earth pony laid down the four of hearts and three of diamonds. "Full house."

Sharp Spear shook his head. "You win again." Ya posh ponce.

"Of course I do." Orange Chance said, gathering up the pot. "It's my noble blood."

"I know your talent's gambling," Rockhoof the earth pony said, shuffling the deck, "but I swear you haven't made a single wrong call."

"I'm out." Blackeye, the sole pegasus in the squad, scooped up his meagre remaining stake and trotted off to join the other moody guards around their campfire.

"Well, not much point with only two of us left." Spear said. "I'm out as well. And I suggest you get some sleep, your worshipfulness. We're starting early tomorrow."

"If you insist. But I don't see why – I mean, you're the ones who'll be pulling the carriage. If you weren't such awful ruffians, I could sleep on the move and be well refreshed for when we arrive in Manehattan."

Sharp Spear grinned. "Seeing as we are ruffians, though, you'll have to get to sleep now."

"I suppose. But don't make any noise!"

Orange Chance lay down inside his tent, and exhaled with relief. He'd been riling up the members of his squad for most of the day, making sure to do it gradually so they didn't just snap and take him back to Canterlot.

It had been hard. These ponies were his friends, and he was used to having their trust. The combination of contempt and irritation bubbling away at the back of their minds was terrible to feel.

And worse still was the occasional faint whisper of suspicion, that their sergeant had known about their upcoming new duty when he left for Stalliongrad.

I'll have to tell them sometime, Mirror thought, behind the mask. I owe them that.

More positively, though, their dissatisfaction was only at the backs of their minds. They were on duty, and they stayed professional.

"Finally." Spear muttered as they reached Manehattan's outskirts. "Maybe we can get shot of him for the day."

"I wouldn't bet on it." Blackeye replied, swooping down from providing top cover. "Knowing what we've seen of him, he'll want to make an impression."

"You presume correctly." The earth pony said lazily from the carriage. "In fact, corporal, we'll park here and trot in – the guard station can't be far. See to it."

Spear rolled his eyes. "Yes, your almightiness Chancellor Puddinghead." Spotting a carriage park, he headed over and began unlatching himself.

"Wish the sergeant were here…" he said to himself. "Even if Shield couldn't handle him, they'd just spark off each other and leave us alone."

The small party didn't have to reach the guard station, as it happened. It only took until they reached the central park for Orange Chance to spot the local guards commander – talking with six mares the sight of whom made Chance's heart sink.

In particular, the dusty yellow earth pony he knew to be the Element of Honesty. She was closely related to the missing Oranges, and so he would have to bluff like never before.

"So, I see you've decided to turn up."

Applejack paused, losing the thread of the discussion completely as the new voice interrupted. "What?"

"What's going on?" she heard Rarity ask. Who, pray tell, are you?"

"This is family business, stay out of it." The new speaker said dismissively. Turning, AJ saw that he was an orange earth pony surrounded by a gaggle of guardsmen. "Now, dear cousin, please stand aside so someone with sense can get to sorting this mess out."

"Are y' talking to me?" Applejack said, confused. "Ah've never seen y' before in mah life!"

"Not surprised. I tend to stay away from associating with the country side of the family, but, well, needs must. Orange Chance, by the way." Chance sketched a minor bow.

"And ah've never heard of you either." Applejack's eyes narrowed suspiciously.

"Oh, that must have been Valencia's doing – he did mention how you'd gone back to the farm, so clearly he didn't want you pining for what you left behind. It's simple courtesy, you see. You don't rub a failure's nose in success."

"Don't you go insultin' me and uncle Orange like that!" The mare was getting extremely irritated, and cantered forwards. Chance skipped out of the way fluidly and backed off.

"I'll do whatever I shall. You may take pride in your country pastures and your simple life, but here in the big city it's who you know, how you comport yourself and, of course, how much money you have."

AJ seethed. Chance seemed to be looking contemplatively at her as he continued backing, maintaining a few yards' distance.

There it was again. A flicker of anticipation, coming from underground and a little behind him.

The disguised Changeling went over his options, and decided to push the Element of Honesty just a little more.

"Though I must point out that for all your family emphasis, the only reason I'm so late is because I had urgent business in Canterlot the very day that Valencia and Berna disappeared. What's your excuse?"

That did it. Heedless of the shouted requests from her friends to calm down, Applejack lunged at the other earth pony and the two of them went rolling across the grass of the central park…

Then the ground gave way, and strong arms gripped them both.

"Hur." A loud voice said. "We got two at once, boss!"

"Then knock them out." Another, more gravelly voice replied. "Fill in the hole, quick, and let's get moving."

Chance had just the time to lock his current disguise in before stars exploded behind his eyes, and he passed out.

Consciousness returned slowly, sluggishly, like trying to walk through cloud.

"Ah see you're awake." A female voice said quietly.

Blinking and shaking his head, Chance looked around. He and Applejack were in a small, well-built cell. Thick iron bars, a heavy door and a lock.

"What happened?"

"Diamond dogs." Applejack practically spat the name. "Musta been what grabbed Uncle and Aunt Orange, and all those other earth ponies. Us, too, now. When ah woke up, they were sayin' that we don't eat unless we work for 'em."

"Right." Chance thought for a moment. "Okay, you're going to have to trust me. I can get us out of here."

"Nothin' doing. Ah bucked the bars, they're solid."

"Not that way. Okay, this is going to take a while to explain, but I'm not actually your cousin." While still talking, Chance began hunting for the letter. "You don't have a cousin Chance. I'm actually with the Royal Guard. Day guard, specifically."

"Huh." Applejack looked Chance over. "Don't recall seein' any guard like you."

"Aha!" Withdrawing the letter, he passed it over. "This covers that as well."

The mare took it, dubiously, and started reading. As soon as he heard her gasp, the changeling dropped his disguise and lit his horn.

"Now, since they only took earth ponies, then they're relying on this lock. They can use it with their hands, and earth ponies would be locked in… but magic means… aha!"

The lock clunked, and with a creak the door swung open. Green flame surrounded Mirror, and he switched to his customary form.

Seeing AJ was staring, he flipped a wing up in salute. "Sergeant Mirrored Shield, Day guard. Now, let's get out of here and find the other prisoners."

"Two. Round that corner." Shield whispered.

AJ nodded, not saying anything, but the guard tasted grudging approval of his talents. There was still suspicion, but the letter seemed to have given her pause and ensured she would give him a chance.

All he could have hoped for, really.

"I'll distract them. You go second – you said you've faced them before, so you know how to handle them."

"Ah do."

"Right. Pity there's no cloud down here, I can do a fairly good thunderclap, but – ah well. Three, two, one, now!"

With a powerful flap, Shield lunged around the corner and straight for the first of two Diamond Dogs. He caught air and avoided a kick, then hissed as claws scored a line across his back – which glowed green and faded near instantly as he shapeshifted the wound away.

The emotions of the dog who had clipped him shifted from triumph to puzzlement, and then blanked into unconsciousness as Applejack smashed him in the head with both legs.

The other dog slammed a haymaker into Shield's chest, sending him flying, then Applejack dealt with him too and hurried over.

"Y'okay?"

"I – argh! Okay, that hurt. Cracked rib? Anyway, I will be." Shield pressed a hoof to his side, and concentrated.

Green fire washed over the area of the impact, and when it cleared the guard rolled onto his legs and stood up. "Ah, that's better."

"What was that? Shapeshiftin'?"

"It was. I was distracted, so it wasn't happening instantly – usually I have a cloud cover layer next to my skin when I fight, so the green light is disguised…"

"Ah'm sure you're proud of it, but we gotta keep movin'."

"Right, sorry." Shield checked the two dogs, whistling. "Wow, you really did a number on them. By the taste of it, they'll stay under until I can have my squad clear the place."

AJ blinked. "Taste?"

"Best explanation I can give, really – without using Changeling words, at any rate, and there's no real point."

"Gotcha."

"Now…" Shield closed his eyes, spreading his sixth and seventh senses wide. "Okay, there's a very powerful mage about a mile off, I can sense him or her from here. I assume that's the Element of Magic – miss Sparkle. Hold on."

With another flash of green, he reshaped his body once more. Wings vanished, replaced by a horn, and his coat became forest green. The mane stayed, and the shield on his flank lost the sheen to become verdigris with a branch device.

Noticing Applejack looking him over, he shrugged. "I invented him last night. Completes the set – I have one each of unicorn, pegasus and earth pony. This one is Bresalac."

"So you don't go copyin' other ponies, but you make up y' own? That's one way t' do it."

"Thanks." Bresalac built a charge on his horn. "Now, miss Sparkle was a student of the Canterlot academy of magic, and I recall they teach the same signalling protocols as the Guard. I may not be much of a mage, but that barely counts as a spell at all."

Three long pulses of green magic flashed upwards. Then three short, followed by another three long.

Twilight, Sharp Spear and two other unicorn guards all startled at the magic SOS coming from nearby.

"Over there!" Rosette said, pointing. "Do you think the Dogs took a unicorn by mistake?"

"Who cares." Spear said, gesturing. "Come on, we need to go save miss Applejack. And possibly Orange Chance, if we can be bothered."

"We are supposed to be escorting him, corp." Rosette pointed out.

"At this point I'm halfway to telling him to argue with the Captain. He'd find it difficult to browbeat someone married to a princess."

"That should get them running." The changeling shifted back to his Mirrored Shield body. "Now they know where to dig, we'd better go after the other prisoners. I happened to pick them up on my empathic sense just a moment ago."

Applejack nodded, then frowned. "Couldn't you sense them before?"

"There was a pulse of stronger emotion, so I noticed. Don't worry, nothing worrying, just surprise. Come on."

"Ah got to ask," Applejack said as they cantered, "Was it hard? When Chrysalis attacked, ah mean."

"Yes, it was." Shield paused, then went on. "I was torn. Oh, I meant my oath of loyalty, and I'd never betray her majesty… but I felt like fighting other Changelings was a betrayal itself."

"I can imagine." The mare said, thinking back to Discord's attack. "How'd you work it out in the end?"

"I shielded my squad, and pointed out Changelings in disguise. I could do no less, and could not bring myself do more." Shield shook himself, and slowed. "They're just around here. I'll unlock the doors, then we go in."

"Can y' do it, without a horn?"

"No. I'll improvise." The changeling concentrated, amending the mental groove of Mirrored Shield inside his mind.

A small horn formed in an ember of green, then lit. AJ stood back a little – seeing a green glow on a white horn was just wrong.

His muzzle sheathed with sweat. "Ergh… doing all fifteen or so at once isn't easy… there!"

A series of loud clunks sounded, and the doors began to swing open. Earth ponies in various states of resignation or defiance looked up, incredulous, then charged out at the suddenly outnumbered Dogs.

AJ charged right in with them, looking for her aunt and uncle, and after a moment to remove his horn Shield took to the air to help.

By the time Twilight revealed the Dog burrow by the simple expedient of telekinetically lifting part of the park up, the skirmish was over. Applejack and her aunt and uncle were hugging, reunited, and Shield had begun organizing the rest of the earth ponies.

"Sarge!" Spear shouted, hopping down into the pit. "What in Celestia's name are you doing here?"

"Good to see you, corporal." Shield replied. "I was in the area, so I thought I'd help out." After a moment, he decided on something. "Actually, could you gather the squad over in that side tunnel for a bit? Got something to tell you."

"Ah'll get the girls over as well." Applejack said, casually. "Ah think they deserve t'know as well."

"Fine." Shield nodded, as calmly as he could. "I'd appreciate you vouching for me."

She agreed amicably. "Least I could do."

"What is it, sarge?" Rosette asked. "She's vouching for you? Sounds unusual."

"I only want to say it once. Sorry."

"Nah, makes sense." The unicorn waved it off. "Was hard enough when I told my family I wanted to be a guard. Imagine, a mare in the guard!" she added teasingly.

"The fact that our rulers are all mares might have been a point in your favour." Shield observed. "Not to mention that new recruit with the hat – did you see her on the drill field? May not be very disciplined yet, but I'd lay evens she's stronger magically than the Captain."

"Yeah, I know who you mean." Rosette agreed. "I'm happy with where I am, though."

"Without you, none of us would know where we were on field manoeuvres."

"Yeah. It may not be as flashy as some, but direction-finding is a perfectly respectable talent."

"We all know!" Shield said, chuckling. "That spell you whipped up for finding the best restaurant for us is a real time saver." He kept chuckling for a moment, then sobered and saw that all ten other ponies were assembled for him to speak to. "Thanks, Rosette. For keeping me occupied."

"No problem, sarge. Now, let's hear it."

"Yeah!" a pony Shield recognized as the Element of Laughter added. "I want to get to the bit where I plan a everyone's-been-saved party!"

"Okay." Shield took a deep breath, and shifted to Orange Chance before dropping his disguise entirely.

He winced, waiting for their reaction. It wouldn't be good. Their emotions were already becoming confused, and he couldn't pick anything out.

"You utter rotter!" Blackeye shouted. "I can't believe I trusted you! I mean, that's… that's… cheating!"

Spear and Rosette looked at him. "Eh?"

"He's an empath – which, actually, explains a lot – but that means he knew when I was bluffing! You'd better give me back most of what you won off me in that poker game!"

Mirror blinked. "Wait, that's it?"

"Look, sarge." Rockhoof said. "You told us when you didn't have to, which means you're guilty about it. And all of us can see you've been the same for years. So that means you're the same pony we've known since basic. We're not going to abandon you over that."

"And as for mah friends," Applejack said smugly, "Ah just showed 'em the letter you showed me the moment you said it. Keep a better eye on that in future, you hear?"

"Wait." The Element of Loyalty asked, frowning. "So where'd this guy come from, and where'd the real Orange Chance go?"

Her friends looked at her incredulously, then shook their heads.

"Come on, guys! Have I missed something? …guys?"

"Excellent work." Celestia said, smiling warmly. "I've received a report from my student about it already. Apparently the lesson to be learned was that you shouldn't always expect the worst, especially if what you're worried about is how your friends will react."

"Sounds about right." Spear said, kicking lightly at Shield. "Sarge here certainly needed to learn that one."

"Ah, shut it." Shield retorted, grinning.

"And it is good to know that I can now rely on all of you to help him in his… additional duties." The diarch continued, eyes laughing.

"Wait." Swift Runner said, slowly. "Does that mean we'll have to do the disgruntled guard thing more often?"

Shield shrugged. "It's entirely possible, lads. And lass."

"Say better, certain." Celestia commented. "It worked well enough here that I'd insist you do it at least once more."

"Ah, bu-buh-bah waaah," Blackeye stopped just short of swearing in front of the princess. "Er, fiddlesticks."

Mirror, sergeant and changeling, took a moment to luxuriate in the emotional mix of the room. If anything, their bonds were stronger than ever.

Yes, things were working out well. And hopefully they would only improve.

AN: So, I continued this.

Mirror's alternate forms

Name: Mirrored Shield

Breed: Pegasus

Colouring: White, silver mane

Talent: Negation of attacks via hardened cloud layers

Method of faking: Regeneration of injuries by shapeshifting, using cloud layers to disguise the flare of light

Name: Orange Chance

Breed: Earth pony

Colouring: Burnt orange, yellow mane

Talent: Gambling

Method of faking: Empathic sense to tell when others are bluffing

Name: Bresalac

Breed: Unicorn

Colouring: Forest green, silver mane

Talent: Camouflage spells

Method of faking: Shifting colours to break up outline

His squad

Sharp Spear, unicorn(second in command of squad). Speciality: piercing attack spells.

Rosette, unicorn. Speciality: direction and location spells.

Blackeye, pegasus. Speciality: lightning crafting.

Swift Runner, earth pony. Speciality: speed and charges.

Rockhoof, earth pony. Speciality: static defence and offence.