For an excruciatingly long five minutes, there is nothing but completely dead silence as the Princesses process what they see. Luna is pale, Cadance is horrified and Celestia appears simultaneously surprised, angry, and distressed. Twilight walks closer at a cautious pace. "Princess?"
Almost immediately though, she and Nightmare Moon find themselves knocked back by an invisible force. After righting themselves, they find that the Princesses are gone. "Cowards. No matter."
Twilight walks over. "Now what?"
Nightmare Moon just smiles. "We continue trying to help Scootaloo. There's a few surprises waiting for them when back at Canterlot Castle."
Luna end Cadance abruptly appear as the latter looks to her aunt in confused horror. "What the hay was that?!"
Luna looks grim. "That was what a corrupted pony looks like. That would be what anypony that opposed Nightmare Moon would have ended up looking like if we had won. Things have just gotten a lot more painful and complicated for all of us."
Cadance looks at Luna hopefully. "If we banish Nightmare Moon, won't they just go back to normal? Dark magic spells only last as long as it's creator. Or won't the Elements purge the darkness inside them?"
Luna shakes her head. "When we created the Nightmare Shadows, we made sure that any corruption would be permanent. Dark magic does fade with its user but the Shadows corrupt a creature down to thier very inner magic. It's why the Elements could save us but the Crystal Heart couldn't do the same for Sombra. We used dark magic, Sombra was consumed and became a living part of it. The Elements and Crystal Heart purge dark magic and leave the good behind but they just banish the entire creature when there's nothing left to save. This was ultimately supposed to be a final act of vengeance in case anything happened to us. The corrupted ponies would attack indiscriminately until they either killed everypony or were killed themselves. We still held a grudge against our subjects for 'disrespecting' the night. How it rendered the Elemental protections useless though, we have no idea."
Cadance looks up with an almost desperate hope. "Can't we just talk them down once Nightmare is gone? Fluttershy managed to redeem Discord after-all."
Luna shakes her head decisively. "When a pony is corrupted this deeply, who they become is left completely up to the whim of the corruptor. They can be anything from the same pony they were with a newfound loyalty to a completely feral and mindless husk whose only job is to kill. Knowing Nightmare Moon, they've become little more than bodies masquerading as who they were just to torment us. She wants us to lose all hope so we either can't or won't use the Elements. By comparison, Discord was never truly evil. What he did long ago and last year was awful but that's just in his nature. Being evil requires malice, anger and actual intent to cause harm whereas Discord is just annoying though he can hold a grudge. He does what he does for fun and because he needs it in order to exist at all. It just so happens that his idea of 'fun' is either extremely inconvenient or completely detrimental to everypony else. Calling Discord as evil as Sombra or Nightmare Moon is like saying that the Timberwolves are pure evil just because they need to eat us to survive."
The conversation is then cut short when Celestia enters with a familiar chest. Before she can speak though. Cadance looks at her aunt in mild frustration. "If we were going to use the Elements, why didn't we take them with us before all this?"
Celestia sighs. "Because they can only ever be used once by anypony other than those they are bonded with or they just refuse to work. It was more or less a security measure to ensure that no-creature could use it for less than noble reasons. We could have just blasted down the dome with them but would then have had to fight our way through her army and defeat Nightmare Moon whilst exhausted. Only the Elements have the power to banish them all but we only have one chance so we kept them here under heavy guard to prevent them from being captured. As you saw, it turned out to be a good idea. Myself or Luna could have summoned them in an instant had Twilight and the others made it out safely but now we need to regroup."
Almost immediately, there is a firm knock at the door. "Come in."
To thier surprise, Aegis Shield is the one to enter with a deep bow. "Your majesties, the Night Guard and Wonderbolts have arrived. The Shadows have yet to leave Ponyvile but it's only a matter of time."
Luna nods gratefully to her right-hoof pony. "Thank you, Commander. Please tell the men to get what little rest they can. We'll be on the move as soon as possible."
Cadance takes a moment to look at her aunt. "How?"
Luna chuckles emptily. "When we create our Guards, we use a lesser form of dark magic to enhance them and give them that appearance. Works wonders with intimidation and apparently vastly enhances thier life-spans. The Wonderbolts must have been too fast."
As Aegis Shield bows and leaves to prepare, Celestia levitates the Elements onto each of them; Kindness and Magic onto herself, Laughter and Generosity onto Luna and finally Loyalty and Honesty onto Cadance. For the sake of wearability, the necklaces have once again become leg armour with Celestia wearing the Element of Magic in place of her own crown. "There, this should help spread out the energy drain. We'll be needed to help out in the aftermath and can't afford to be too weak." Cadance could have sworn she saw her aunt subtly shudder for just a moment when putting the Elements on for the first time in a millennia. Her reaction is as if she were struck by a very sudden Arctic breeze or she were doing something she isn't entirely comfortable with. Before she can check, her look has been replaced by one of grim determination. "Remember, they may look like our friends but they're not anymore. We're doing what we must to protect everypony else. We can't allow this to spread."
When the three turn to leave though, there's a loud supersonic bang as Night-time Flare bursts in through a side door, does a loop-dee-loop and lands. Wary, Cadance and Luna aim thier magic towards the new Alicorn even as Flare takes a moment to deeply bow. "Aw, c'mon. Is that really necessary?"
Celestia looks at Flare severely. Not an angry or frustrated glare mind you but instead a deeply disappointed gaze. Coming from her though, it's kind of like being slapped in the face. "Considering recent events, yes. We can't trust that you aren't here to attack us." Her gaze turns hopeful. "Please Rainbow Dash, fight it. We don't want to have to do to you what I did to Luna because, this time, you won't be able to come back."
Flare sighs. "Princess, I'm still me. I'm not here to take over Equestria, I'm here to help everypony else."
Luna trots forward. "Rainbow Dash, we know that you probably mean well but you must have heard the old saying. The road to Tartarus is paved with good intentions. Nightmare Moon is an excellent manipulator; she could sell water to a drowning pony. Look at everything that's happened; Nightmare Moon is free, Scootaloo is crippled, and an entire town has been corrupted. This has to stop, one way or the other."
After visibly wincing at the mention of Scootaloo, Flare eyes the Elements knowingly whilst the three Princesses just look at her blankly. "Look, I know that how I did it was... less than great but this was the best solution I could find."
Celestia frowns critically. "The Elements, the Crystal Heart and the eight of us are more than capable of stopping any threat. We wanted to help our little ponies so that they can defend themselves until we can help."
Flare returns the expression. "And look how incredibly well that turned out with the Changelings. You were defeated, we were captured, the Elements were completely useless without us, the Royal Guard were helpless and that Queen came horribly close to turning Equestria into an all you can eat buffet. If not for Princess Cadance and Shining, I don't want to even imagine what could have happened."
"Queen Chrysalis."
Flare turns her gaze to Luna. "You know her?"
Luna nods grimly. "Celestia and us share an... eventful past with her. Although you certainly have a point, we can't condone everything else. One way or another, Nightmare Moon will be gone by nightfall."
Cadance is next to speak. "What was your plan, Rainbow Dash? Run around Equestria and forcibly corrupt everypony whilst scaring them silly?"
Knowing that this conversation is going around in circles, and getting an urgent mental tugging sensation through her connection with Nightmare Moon, Flare decides to reveal the real reason she is there. "Hate to fly but I'm needed back in Ponyvile. Before I go though..."
Flare casts a quick spell and flies back out through the main throne room doors. The two stationed Guards move to intervene but Celestia calls for them to stop. "Trying to stop her without the Elements is futile when we need the energy for the Nightmare Shadows as well. We need to wait until we're ready to move on the ent-"
Her voice trails off as she spies some unnaturally dark shadows in the corner of the room seem to vanish as a very familiar stallion approaching them with a nervous trot. "Cadance?" Sharing a look, Celestia and Luna back off slightly; staying close enough to help but giving thier niece a moment.
Shining Armour turns his gaze to his wife whose body is tense but she wears a completely unreadable expression. "Cadance, I-" He walks right into an energy shield. "Cadance, I'm still me."
After a very long and very uncomfortable silence, Cadance fires off a spell which makes Shining Armour drop like a basket of apples. After a moment of awkward silence, Luna approaches the body. "Is he...?"
Cadance shakes her head. "He's just under a very powerful sleeping spell and won't wake up until tomorrow afternoon. Once this is over, I'll deal with him." She turns to Princess Celestia. "I know you said that they're beyond saving but.. I have to try. If not for myself, for Night-light and Velvet. It might be completely hopeless but I have to be sure."
Seeing the hope in her neice's eyes, Celestia nods reluctantly after a moment but only after putting a magical inhibitor on Shining's horn. "Please just remember that you might not be able to save him, Cadance."
Cadance nods sadly. "Then I'll put him out of his misery. It's what he would have wanted." After taking a moment to teleport her husband to the dungeons and take a deep breath, Cadance turns her attention back to the matter at hoof. "Any idea why Rainbow Dash left in such a hurry?"
Celestia shakes her head and the three Princesses begin the final preparations before confronting Nightmare Moon one last time. Around half an hour after the impromptu visit however, a Wonderbolt messenger suddenly soars in and hoofs over a scroll before collapsing in exhaustion. Exchanging a mixture of concerned and confused looks, Celestia unfurls the scroll to read it aloud.
To Princess Celestia\Princess Luna\Princess Mi Amore Cadenza
I can only hope that Marathon Flight reaches you as quickly as possible. The Nightmare Shadows have left Ponyvile and are headed towards the southeast. The residents of Ponyvile have stayed behind in the town and don't appear to be doing anything unusual. What are our orders?
With respects
Crystal Skies.
Celestia looks up completely baffled. "But the only things southeast of Ponyvile are Rambling Rock Ridge, Baltimare and..." She trails off for a moment when a rather horrifying realisation comes to mind. "The Dragon Lands."
Luna looks at her sister curiously. "We're not sure that Nightmare Moon's corruption would work on dragons. Thier type of magic is much different than a pony's."
Celestia shakes her head. "Even if that's true, or they are headed to Baltimare instead, we can't afford to take that chance. We can't afford to lose more ponies and, if the dragons were turned against us, there would be mass devastation. We have to move, now." The possibility of gigantic, feral dragons at least as big as Spike was on his birthday last year torching Canterlot and hunting down her ponies to eat makes her breath hitch.
Exchanging a look with the other two, who begin preparing themselves for a long and fast flight, Princess Celestia abruptly teleports to the war room. Upon arrival, she finds that the leading elements of both segments of the Royal Guard are busy arguing over the best defenceive strategy. After a moment of stunned silence, they bow. "Commanders?"
Aegis Shield and the Day Guard's commanding officer Solar Strike step forward. "Yes, Princess?"
Celestia allows herself a small smile at how they can go from arguing like schoolyard foals to regimented, disciplined professionals in seconds. "Please organise a regiment of your best soldiers to be ready to move as soon as possible. The Shadows are on the move towards Baltimare and the Dragon Lands so we can't afford to wait." The two Commanders nod professionally and bow before hurrying away to organise the force. "Everypony else will be needed here in case this turns out to be a trick. Remember, they are weak against light." The rest of the Guards nod as she teleports back to the throne room to sure up the city's defences.
Arriving at thier previously agreed meet-up location, Flare finds Nightmare Moon waiting impatiently in her living room. "What's wrong?"
Nightmare Moon looks grim. "Scootaloo is gone."