After a short time, the ponies were called to the medical tent for briefing, so that Rainbow could hear the discussion as well. Celestia addressed them all in a very harsh and commanding tone, quite different from her usual soothing voice. It wasn't quite on the level of the Royal Canterlot Voice, but it was sufficiently loud to make even the strongest-willed ponies recoil a bit.
"You've all used the Elements of Harmony before, so you shouldn't need much instruction. However, you must keep in mind that you aren't facing a single creature, but an entire army of them. You will have to be fast. You will have to be vigilant. Discord was once a genius, so he was able to entertain himself with head games, but these creatures— the great majority of them are ignorant brutes. Now that they have been corrupted by these magical artifacts, they will crave nothing more than to tear ponies to shreds, with special attention paid to the Elements of Harmony. If you don't destroy them before they can reach you, there won't be a second chance. There won't be friendship letters and memory spells. You will die. Do you understand?"
Most of the ponies nodded in agreement, except for Rainbow Dash, who grimaced, as though in pain.
"Do you take issue with this, Rainbow Dash?"
"No, it's just... I... Uh," she replied, looking desperate for any answer, "just my wing. It hurts."
"What happened out there, Rainbow Dash?"
"Nothing! They attacked us... caught me off guard!"
"What happened?"
"Nothing!"
"To whom does your loyalty belong?!" Celestia asked, growing increasingly belligerent.
"To you! To Equestria!" She yelled, on the verge of tears.
"I'm glad. I know when a pony is lying, and you are not. But I was worried; understandably so. I know you have certain... connections, with the griffon kingdom."
"Not anymore... Gilda is a monster..."
"Good," Celestia continued, "Now, back to the briefing. Our soldiers are not equipped to fight these creatures. Not with any reasonable chance of success. However, they will be able to hold the griffons back, for a little while. Hopefully, this will buy you enough time to move along the frontline and eliminate hostiles one at a time. Do what you can to prevent pony casualties, but above all else, keep yourselves safe. You are the only chance we have. Now, you must prepare for battle. Get yourselves fed and then report to the armory for fitting. Griffons are known to take cheap shots and you will need to protect your bodies from harm. Plus, the passive cloaking systems will allow you to move around... slightly less conspicuously."
Celestia then yelled into the back of the tent, to nobody in particular, "And as I said before, I need the absolute best physicians working on Miss Dash. She must be fighting fit as soon as possible. That's an order, not a request."
With that, a couple more medics moved in on Dash, crowding around her and chattering quickly.
"And one last thing. On the battlefield, you may find small, spherical objects being dropped by deceased griffons. Do not pick them up, do not touch them, do not even LOOK at them. Twilight already knows why, but trust me when I say you don't want to find out. A trained team will be dispatched to clean them up, once the battle is won."
Celestia made her way out of the tent, to tend to other matters, leaving the Bearers of Harmony alone. Sans Dash, they moved towards the canteen, talking on the way.
"Why do y'all think she came down hard on Rainbow like that?"
"I don't know... This war stuff is pretty serious," Twilight replied.
"But Rainbow? A traitor?" Rarity asked rhetorically.
"Loyalty to somepony else is still loyalty, Ah reckon."
"Yeah," Pinkie reaffirmed, "like when Gilda came to Ponyville! Dash was totally being loyal to her and not even thinking about me for a second!"
"Wait, Gilda?" Rarity pondered, "I knew I recognized that griffon! She was the one who was attacking Dash!"
"Gilda did that to her?! Oh, she really is a mean meanie-pants!"
"But Rainbow knows her! Do do you think she might be on their side?"
"Nah, Celestia just said she wasn't lyin', and Ah don't think she was either. She did look bothered about somethin' though."
Twilight piped up. "She's probably just a little shaken up from being overpowered like that. I suspect she'll be back to her headstrong self in no time."
"Ah sure hope so. I don't like to admit it, but a lot ah the time, her cocky attitude is kinda inspirin'."
"Even though it can be annoying, at times, I know what you mean."
"Um..." Fluttershy uttered, almost silently, attempting to interrupt in the politest possible way.
"Yes, Fluttershy?"
"Well, it's just... I think she's scared."
"Rainbow Dash? Scared? Of what, exactly?"
"Oh... um... well... Of herself."
"Huh?" All four of the other ponies uttered in unison.
"Something she did out there. She feels... guilty for it."
"She already apologized for that, Fluttershy, remember? She said she was sorry for leaving camp."
"No... She knows we'll forgive her; but there's something else. Something she can't forgive herself for."
"What is it?"
"I um... I don't know. But that look in her eyes... I've seen it before. Back when we were foals."
"What was it about back then?"
"I never found out..."Fluttershy replied, staring longingly into the distance, "but it was years before Dash was back to normal again."
"Let's hope it's not the same this time around, then!"
"I really hope I'm wrong..."
"Well, you know Dash better than anypony. Do you know anything we can do to cheer her up?"
"Not when she's... like this... I don't think she ever smiled back in those days."
Applejack sighed. "Well, we can try and make her feel better once they patch her up. But there's not much we can do right now. We should grab somethin' to eat while we still can."
"I'm absolutely famished! What do you think they have here? Is there a menu?"
Twilight answered quickly, "It's a makeshift military base, Rarity, I'm sure that whatever they have, it's going to be practical and boring."
"I'm almost willing to eat grass, at this point."
"Oats?" Pinkie asked, frowning, "There's like, hardly even any sugar in that!"
"They're enriched oats," Twilight explained, "Not the most delicious stuff around, but it'll keep an army going strong."
"At least it's not grass..." Rarity rationalized.
At that point, everyone looked to Applejack, awaiting her opinion, only to find she was already half-way done with a bowl. She looked up, and while still chewing, said, "When you're really hungry, they're practically gourmet."
"Applejack, don't talk with your mouth full. I'm going to lose my appetite before I even get started!"
Twilight and Fluttershy ate at a normal pace, while Rarity and Pinkie only ate a little bit, mostly just prodding the oats with their utensils, looking distraught.
"That wasn't bad at all, ya'll think they'll let me get seconds?"
"May as well ask... If they won't give you more, you can finish mine, I'm trying to watch my figure, anyway."
"As if ya have any more pounds to lose off that bony flank ah yours," Applejack teased while she approached the kitchen.
"Well, I never! Never mind, you can't have any." Rarity replied, defiantly taking a few more bites of oats.
"That's more like it!" AJ said as she sat back down with a second bowl.
Rarity looked at her, baffled, before realizing what had just happened. "Hey, that's not fair!"
"Go on, finish it. I've seen ya eat twice that much in one sitting."
"She's right, Rarity. Eat up. Using the Elements can take a lot out of you; you'll need the energy. You too Pinkie."
Both picky ponies increased their pace a bit, though neither one managed to enjoy it. Upon completing their meal, the group was guided to the armory.
Rarity was selected first to be sized up; a pony took a measuring tape to her, scribbled a few numbers on a piece of paper, and left the room, returning moments later with a pile of royal guard gear in her size. She began slipping herself into it carefully, so as not to disturb her perfectly groomed mane.
"This is demeaning... not fabulous at all." She said, as she squeezed the helmet onto her head, flattening her hair down in the process. "So, how do I look?"
Twilight maintained a serious expression, while Applejack raised her hoof to her mouth, snickering. Fluttershy smiled a bit, trying to hide it behind her own hair. Pinkie wasn't paying attention, but when she turned to look...
"Bwahahahaha! You look like one of the guards!" She chortled, falling on the ground and rolling over.
"I don't see what's so funny about that, I'm only wearing their armor."
"No," Twilight said, obviously trying to stop herself from catching Pinkie's laughter, "she means you look exactly like one of the guards. I guess that's what Celestia meant by 'passive cloaking.'"
Rarity rushed to the nearest mirror and examined herself closely. Sure enough, her beautiful feminine form had been replaced with that of a royal unicorn guard, a light grey coat, blue eyes, strong square muzzle. She frantically tore the helmet off, and was relieved to see her own face and mane again. Her hooves frantically and desperately tore through her hair in an attempt to restore its usual curl.
"No! I shan't do it! It's undignified!"
"It's just a uniform, lady. It'll help you blend in. Did you really think we all look like that? Where do ya think Celestia could find some-odd five-thousand ponies with the same color coat?"
"But I look hideous in that... that... thing!"
"You know, Celestia chose our appearance herself, I'm not sure what she was going for, but 'hideous' probably wasn't the word on her mind."
"I have dignity! I have rights!"
"Well, you can hold onto those if you want, but if you want to keep your head, I recommend the armor. The griffons do have spies, and they know what the six of you look like. If they see a big bouncy purple mane running up and down the trenches, where do ya think they're gonna aim?"
"I'll think about it," Rarity growled, gripping the helmet in her teeth and trotting back to her friends. She dramatically dropped down onto the floor, resting her head and front forehooves on top of the helmet to watch the rest of the fittings.
The others were fitted without hassle, each taking on the form of a type of royal guard, Fluttershy a pegasus guard, and Applejack and Pinkie as Earth-pony guards. The only one who still needed gear was Twilight. The worker doing the fittings approached her, only to find that his measuring tape wouldn't even cover her full height. He stepped back for a moment to get the whole picture.
"I don't think I can help you, actually, we only stock the basic range of armor sizes. The princesses have to have their armor custom made... and that would take weeks."
Twilight thought for a moment, before mumbling "No problem, I mean, Nightmare Moon... I've got this, just let me..."
She stepped in front of the mirror and looked herself up and down. Exerting but a modicum of effort, she began to convert the thin air around her into tough metal by means of direct nuclear manipulation. Everyone else in the room watched in wonderment as the armor simply grew around her like minute plant roots, which eventually fused together into solid plates. With a little tweaking, she was able to imitate the style of the royal armor quite well. She moved her limbs around, checking to make sure the joints worked.
"So? Whaddaya think?" She asked the guard, smiling. He muttered something incoherent in response, and then just nodded. With a little more effort, she applied a cloaking spell, making herself a boring white unicorn just like Rarity had become. Only... two feet taller.
"Well, I guess I'll blend in a little better," she added, blushing so intensely that red could be seen through the cloaking spell.
Now that they had been properly prepared for battle, there was little left to do other than wait. The five ponies stood on the outer wall of the ancient fort, staring out towards the frozen ocean. It was a strangely beautiful sight, despite the fact that such a thing should never be. Not this far South. Not during the Summer. Out in the distance, the clouds that Dash had set up were performing their respective tasks, building up an effective defensive barrier that would funnel the griffons into a manageable cluster.
After about an hour, Rainbow's medical care was concluded, and she joined them, also fitted with royal armor.
"The doctors say I'll be okay..." she muttered, "but I'll need to stay off my wings for a week."
"Oh... Dashie..."
The ponies expressed their sympathy towards her and gathered into a group hug, contemplating in that moment what had already happened and what was waiting for them in a matter of hours. They knew what to expect from the East, over the ocean, but they couldn't have possibly expected the incredible force, neigh, the oncoming storm, approaching from Ponyville in the West. Derpy was on her way.