Shades of Grey

by Inquisitor M

14. Out of Time

“I’m not picky, so don’t be too upset if I start with the most helpless among you.”
A purple aura built around Luna’s horn, accompanied by a rising hum, and a torrent of energy spewed forth—not the focused arc that struck down her guards, but a writhing, surging mass of lighting that sundered the earth.
A hail of dirt pinged off the leg shielding Rainbow Dash’s face. “Rarity!” she cried, landing by the steaming gouge where her friend had been moments before.
Luna lifted her muzzle to the sky and laughed—a full-bellied, maniacal cackle that made Nightmare Moon sound positively sane—but fell silent when a pink pony growled right under her nose.
“Okay! No more Miss Nice-Pinkie. Nopony, and I mean no-pony, gets to hurt my friends!”
Luna held Pinkie’s stare without blinking.
“I admit I was expecting more… distress. No matter. I have time to kill and you do not.”
Rainbow Dash twisted back and forth, scanning her surroundings. Fluttershy quivered, curled into a ball and peeking from behind her hooves, but Applejack shared Pinkie’s defiant stature, a grin spreading across her face. Dash looked around one more time. “Oooh, I get it.” She leapt into the air, puffing out her chest and striking a heroic pose. “You’re nothing but a big old bully. I bet you can’t hit me.”
“Ah reckon so, Rainbow Dash. I guess we do this the old fashioned way,” said Applejack, straightening her hat.
Luna snarled, and another purple aura formed around her horn. A quicker, leaner arc of lighting lanced through the air, but Rainbow Dash was already speeding away, poking her tongue out at the princess.

Twilight stared at the whimpering pony curled up at her feet. “Rarity, I…” She brushed stray hairs from around her friend’s closed eyes. “I’m sorry. Princess Luna said you were going to be okay, and… I just assumed…”
Rarity shook with each slow sob, hugging her tail against her face. With barely a chance to breathe, those sobs were the convulsions of an empty pony.
“Rarity…” Twilight lowered herself and nuzzled the back of Rarity’s head, but jerked away when the scene flashed purple, followed by the fizzing of more lightning. In the distance, Rainbow Dash arced and twisted through the air, a continuous aerobatic routine that stayed one manoeuvre ahead of her attacker.
“I have to go,” Twilight said firmly. “Whatever happens, somepony is going to have to stop her first.” She stood, her expression turning dark as lips pulled back to show gritted teeth. “I won’t let her hurt anypony, and I’ll be back for you as soon as I can. I promise.”
More lightning fled into the night sky followed by Rainbow Dash whooping and cheering.
“No, I swear. I swear by Celestia. I’ll be back.” She vanished in a purple backwash of magic.

“Is that all you got?” Rainbow Dash waved her rump in mid-air like a rainbow-coloured rag to the wrath-filled bull in the clearing below. Another flash speared nothing but empty sky as Rainbow Dash dove. “Are you trying to make this easy?”
Applejack peeked from behind a tree. Each time she tried to clear the distance between them, Luna spotted her instantly, and the two second delay before each attack didn’t even get her halfway into the glade. Only shattered and blackened stumps remained of her last two hiding places.
Fluttershy stood within a hoof’s reach of the princess.
“Umm… excuse me?”
Luna lashed out with more lighting, her eyes following Rainbow Dash.
“Ex… excuse me? Could you please stop shooting at my friends?”
Still the princess ignored her, launching more attacks into the sky.
Fluttershy’s brow furrowed and her lips pursed. “Hey!” she screamed. “Stop attacking my—” Luna’s wild eyes turned on her and Fluttershy shrank down. “Please?” she finished in a tiny squeak.
Luna’s horn glowed.
“Oh no ya don’t!” Applejack thundered across the hard earth. “You leave her alone!” There was no lightning. Instead, as Applejack spun and bucked, a blazing white sphere of energy exploded from Luna’s horn. The blast flung her away as if she were no more than a paperweight, straight at the trunk of a large tree.
“Gotcha.”
Applejack’s hooves flailed for a moment. She hung in the air, wrapped in a blanket of lavender magic as Twilight stomped past her. “Whoo-ee!” she cried, falling in beside Twilight once she was on the ground. “Much obliged, Twi. How’s Rarity?”
“I don’t know,” Twilight said curtly. “She’s safe, but I want to know what’s going on.”
“Well, ya sure saved my keister, sugarcube. But whoever that Luna-like is, she couldn’t hit Rainbow Dash for all the apples on my farm—keen pair o’ eyes, but she ain’t got a full set of wheel on her wagon. Figure that’s the only thing we got goin’ for us.”
The once-small glade was now hundreds of yards wide. Ripped and shredded earth surrounded Luna: only tree roots and a few stumps remained in place, the rest brushed aside as easily as cobwebs. The dishevelled princess clenched her jaw, eyes wild and twitching. She continued firing at Rainbow Dash, and Applejack smiled as Fluttershy swooped past with no signs of injury.
“Thank Celestia she’s all right,” Applejack whispered. Luna’s attention snapped towards her, horn glowing. “Look out, Twi!”
The lightning tore through empty space.
“I don’t know who you are,” Twilight said, appearing right in front of Luna. “And I’m not sure where you came from, but could you at least tell me why you’re trying to hurt us?”
Luna’s face softened. “So you were paying attention after all.”
“Yes. Yes, I was. You said you wanted to hurt us enough to bring ‘her’, and I didn’t know who until now.”
Applejack cocked her head.
“You said ‘thank Celestia’, and this fake-princess went straight for you. That’s who you want, and you want her to come and rescue us, right?”
Luna’s lips curled into a wicked smile. “Oh, very good, Twilight Sparkle.” She chuckled, then drew it into a self-satisfied purr. “But you made one important mistake, little Twilight. I’m. Not. Fake.”
“Ah don’t believe you!” Applejack cried.
“Irrelevant.” Luna moved nose to nose with Twilight. “Miss Sparkle believes me. Don’t you?”
Twilight backed up a step. “No! I don’t... I…”
“Yessss…” Luna pressed forwards, keeping in Twilight’s face. “It makes sense, doesn’t it? What better tool to torture her than her sister? And all the sweeter because she let me in! Somewhere inside she wanted me to take revenge for her. How lucky she is that I was here to give her such a gift.”
“No!” Twilight stamped a hoof, holding her ground against Luna’s advance. “I won’t believe it. Luna would never do that! She’s changed!”
Luna burst into crazed cackling. “As you wish, fools!” Her voice boomed as she pulled up to her full height. “You have but one chance to save yourselves from suffering. Call her—bring Celestia here—and I will spare you your torments.”
“Not a chance!” Rainbow Dash yelled from above. “You can’t even hit me! We’ll never back down from the likes of you.”
“Eeeyup,” Applejack said.
Luna grinned. “You realise, of course, I don’t want you to back down. You can’t hurt me. You won’t risk hurting dear Luna. All you can do is scamper and run until I catch you. So run, wretched little ponies. Run while you still have breath left. I can keep this up forever!”
Luna’s horn glowed, and Twilight vanished. She appeared with Applejack at the edge of the clearing, but there was no stroke of lightning passing through where she had been. Above, Fluttershy yelped as the bolt rose into the sky instead.
“Fluttershy!” Rainbow Dash cried.
A second lightning bolt grazed Fluttershy’s shoulder and the pegasus tumbled through the air, out of control and a blackened scar across her coat.
Twilight stared. Everything happened so fast, yet time seemed to slow as an icy grip squeezed at her heart. She watched Rainbow Dash arc downwards and collect Fluttershy in her hooves—watched her roll, placing herself in the way of the inevitable third attack.
Her stomach filled with lead as Rainbow Dash’s eyes squeezed tightly shut, bracing herself for—
Wait a minute…
Lighting crept from Luna’s horn, tiny offshoots visible as it inched towards the pegasi.
Time is slowing down.
There was silence—total silence. Everything had stopped.
Applejack’s blond mane was frozen in mid-gallop. Luna’s face was a portrait of malevolent glee, eyes and wicked grin both insanely wide. Twilight reached out with magic to snatch the pegasi from their dive, but for the first time since she was the smallest of fillies, it would not obey her will.
“Is anypony here?” she called out. “Can anypony hear me?”
“Yes.”
Twilight spun towards the voice, her eyes bulging. “Stormcloud? Wha… what are you doing here?”
“We need to have a little chat...”

Rarity stared at her other self—the one curled into a ball at her feet and frozen in time. Something stabbed at her heart, but the claws that had once bitten deep were blunt, nothing more than an echo. In the silence, she breathed slowly, raising a hoof to examine the ghostly outline of her current form.
What did that book call it? Astral projection? I look just like the ghost I saw in Stormcloud’s cave.
Under cover of a nearby tree, Splashdown’s splinted and bound body lay equally frozen. Beside him, the ghostly outline of Luna coalesced, but the colours brightened and thickened until the princess stood full-bodied and tall.
“Luna! Luna, what’s going on?”
The princess walked forward, her star-field mane larger and more animated than usual, but while she mouthed words, no sound came out.
“I... I can’t hear you, Luna.”
Luna frowned as she mouthed more carefully: Can you hear me now?
“No, I’m sorry Princess. I can’t hear anything.” Rarity’s words quickened as Luna closed. Those eyes… something in those eyes reached out to her, spoke to her, saw into her as they had before—saw the foolish, selfish little filly that still needed another pony to hold her hoof.
She shied away, but a gentle touch under her muzzle drew her back, right into a warm smile and that welcoming gaze. Her body twitched and shuddered—if she were not so undeserving she could just throw herself into the safety of this delicate, but wilful, princess.
Tears filled her eyes and her head jerked to one side: Luna had watched her fail. Another touch stroked the side of her face before gently pulling her back once more. “Luna, I… I don’t… I don’t know what to do. I—” The hoof pressed against her mouth, hushing her as tears rolled down her face like a parade of secret shames laid bare.
Breaths came faster and deeper as the pressure rose; all she had to do was speak, to trust the one she thought could bring her salvation. If she trusted Luna so, then why could she not find the words?
Something touched the back of her leg, drawing it upwards until her hoof was planted firmly against Luna’s chest. The night-blue coat was smoother than silk at her touch and the soft flesh beneath it expanded as Luna inhaled deeply. Another breath and Luna slid her hoof down, prodding Rarity in the chest before holding there in symmetry.
“You… want me t-to…”
Luna prodded again, wearing a slight frown.
“Sorry, I…” She paused, then took a deep breath.
Luna’s smile widened. Together, they shared two more long breaths before Rarity tensed and grimaced, squeezing her eyes tight shut. She felt the rise and fall of Luna’s chest and imagined that kindly smile beaming down at her. She felt Luna’s hoof pressing against her—firm, resolute, connected. Sensation blotted out all else until their synchronised breaths became a single, shared experience—just breathing, just being… being with her princess.
Rarity opened her eyes slowly. “It’s… really you… isn’t it, Luna?”
The princess nodded slowly.
“Are… you doing this? Whatever this is?”
Luna shook her head.
“Stormcloud then? I saw something like this before.”
Another nod.
Just tell her, Rarity. 
Luna’s gaze roamed across her features as she felt the sting of her strained eyes moistening again. The hoof on her chest moved slightly, massaging the spot, and Luna’s smile twitched. She knew that look—the same look Twilight had given her twice. Let me in, it said, I want to help you.
“I… Luna, I’m-I’m sorry!” The words burst from her mouth and Luna’s eyes widened. “I couldn’t do it! I just couldn’t be what you needed me to be, I—”
The princess’s hoof shushed her again, before reaching down and lifting the leg that had fallen away. Rarity flinched as Luna leant slowly towards her and, after a moment’s pause, gently bopped her, snout to snout.
Rarity tensed, trembling until she felt, as much as saw, Luna chuckling softly.
She sniggered, the sound spluttering past her defences—indifferent to the conflict that whirled inside her. She giggled, and Luna giggled with her.
Luna was still here. Despite the words, Luna was still here! For a moment, it all seemed utterly absurd. Yes, Luna was here. Luna was safe. Luna saw the pain inside her. Luna saw… everything.
The dam cracked, pierced by those Azure eyes, and a maelstrom of feelings surged through her.  Rarity cried, and bawled, and wailed, like a terrified little filly that still needed to have her hoof held.

The pony looked like Stormcloud, but his demeanour was utterly relaxed, almost jovial, his voice soft and flowing rather than stiff and precise. The silver flecks in his hair and horn were missing. Also, he may have just stopped time. It was a stretch to believe it.
“Please, Twilight, try to remain calm.”
“I am calm!” she shouted.
Stormcloud sighed. “You probably have a head full of questions, so perhaps we should start on those first?”
“Yes!” Twilight began pacing. “You could start with telling me what’s going on!”
“All right then. You may have already guessed that I am not Stormcloud as you know hi—”
“Duh!” Twilight stopped pacing and scowled.
Stormcloud pushed on through the interruption, slowing his words and delivering with more force. “It’s complicated. I’m not a pony, you see; I’m part of that.” He waved a hoof at the time-locked Luna. “Until a few days ago, we were the same being; all those things I said I was forgetting, are still up here.” He tapped a hoof against his head. “This is how the dream felt, and I think it was this part of me that was awake for it, while the real pony slept. That would explain why I—that is, he—started forgetting it after being released. I… sorry, this is difficult to explain. He thought he would have boundless wisdom when he awoke, but that which is me started to separate from that which is him. In a way, I’m glad for it too—otherwise I would not have the will to ask you to do what must be done.”
Twilight closed her eyes for a moment, the serenity of the ‘dream’ beginning to seep into her mind and her muscles—except she wasn’t asleep, and her muscles weren’t really there. “I don’t understand,” she said, eyes slightly narrowed. “You still haven’t told me what’s going on.”
Stormcloud trotted up and sat next to Twilight, pointing a hoof towards Luna. “Look there, look at the lighting. Look very, very closely, Twilight.”
“What am I looking for? I don’t see anyth—wait… It’s moving! It’s moving… incredibly slowly?”
“That’s correct. I can’t actually stop time. I’ve just slowed your perception of it so that we can have this conversation privately. Now relax, and let the power of this place wash away for fears, if only for a little while.”
“I am,” Twilight replied, letting her head droop as she closed her eyes again. “But it feels so wrong to be calm considering what’s about to happen.”
“I understand. You are rightly worried about your friends, and Luna.”
“Is that really Luna?”
“Yes, but she’s not in control of herself. I’m like a ripple in a pool of pure magic, the echo of the real pony. But those ripples aren’t fading; the smaller nuances—those parts speaking to you now—are lost under a torrent of rage and hatred. That is what controls Luna, but we’re fighting, doing everything we can to resist. That’s why the other part of me has been so unsuccessful in trying to hurt you.”
Twilight frowned, reached out, and poked the stallion in the cheek. “You know, you really don’t sound like Stormcloud.”
“I suppose I don’t.” His voice softened as he cocked his head. “I don’t have a princess to impress anymore, but your friend seems to know that story, and I think you can come up with better questions than that.”
“Okay then. She… or he, well, you, I guess, said Luna let you in to get revenge on Princess Celestia. Is that… true?”
“A little. Imagine having a friend who knows your worst fears even better than you do—one who uses them to get a reaction.” Stormcloud sighed and his shoulders sank. “It used her weaknesses to get in. She didn’t exactly let us in, but the feelings are real enough. Still, Luna’s changed. She resisted more than it expected, and now she bides her time, waiting for you to do what we ask of you.”
Twilight’s eyes shone. “I can help Luna get control back?”
“Better. I believe you can purge us from her entirely.”
“So what do I need to do?” Twilight replied, starting to smile.
“Get us angry. Being made of hate is one thing, but the more we show it, the less control it has over Luna. I have a few years of experience at beating myself up, so I’ll be helping from the inside. Your rainbow pegasus had the right idea: we were getting deeply aggravated until someone mentioned Celestia.”
Twilight gasped. “Of course! She… I mean, you, were suddenly so focused, you had time to think… you…” She winced, then looked up at Rainbow Dash clutching Fluttershy. “Did we cause that to happen?”
“You couldn’t have known,” Stormcloud said softly. “If it makes you feel any better, my other half genuinely isn’t intent on killing any of you; drawing Celestia out is no longer relevant.”
“What?” Twilight’s attention snapped back to Stormcloud. “Why?”
The stallion raised a hoof right next to her face, pointing at the sky. “Look there.”
A flicker of light hung in the air between Luna and Rainbow Dash. “I see it! I… umm. What is it?”
“In about a half-second of real time, that will be Princess Celestia.”
“But—”
“That’s right, it’ll ruin everything. I need you to make her go away.”
“But—”
“You’re the only one that can do it, Twilight. I don’t know how much she trusts you, but I’m counting on how much you think she trusts you.”
Twilight fell back onto her rump. Celestia? Here? She would appear right in the path of the lightning bolt. That couldn’t be a coincidence; she was here to save them, just as the thing inside Luna wanted. One slip and everything was crashing down around her. “So,” she said with a heavy frown. “All I need to do tell the Princess of Equestria to leave and irritate your alter-ego controlling the other Princess of Equestria until she goes on a furious rampage and tries to kill everypony?” Twilight huffed. “Are you sure there isn’t something else I can do for you in my spare time?”
“Actually…”
“Of course!” Twilight yelled, throwing her hooves in the air. “You wouldn’t want this to be easy, would you?”
“Now, now.” Stormcloud’s voice rang with his former, jovial cadence. “That kind of sarcasm isn’t befitting of you, Twilight Sparkle. You’ve already figured out how to do it, you’re just afraid that you’re not strong enough to do it.”
Twilight gave another petulant huff. “Yes. The Princess is saving Rainbow Dash and Fluttershy, so I just have to save her. Are you reading my mind again?”
“No, that much is written on your face. You’ll manage it, because it’s for her. Have a little faith in yourself, Twilight.” Stormcloud flopped to the ground beside her. “This is the gift I give to you: knowledge. The thing you treasure most. Luna and your friend are experiencing my gift to them as we speak, and unfortunately, it’s going to get me noticed very soon. That means I won’t be able to do this again. That leaves only one thing remaining.”
Twilight sighed, letting her head droop. “I’m not going to like this, am I?”
“I’m afraid not, but Luna and I are in agreement. Whatever happens, I must be destroyed utterly.”
Twilight fixed him with a wide-eyed stare. “How can you possibly say that so calmly?”
“I don’t think I need to answer that: you would give your life for your princess, and I, for mine. It won’t stop, Twilight. Not ever. Not even if it kills Celestia. And this isn’t going to get any easier, either. Once my other half is no longer limited by Luna’s will, I have no idea how strong it will be. Twilight?” He waited for her eyes to refocus on him and gave her a wide smile. “Don’t try to overpower it, okay? Forget what I said before about power and control. You’re smart, Twilight. Let the rest come naturally.”
Twilight gave no answer. Instead, she lay down, closed her eyes, and let tranquility wash over her. Complex spells and calculations flashed through her mind in sequence, each formula influencing the next. There would be no second chances here, but Celestia’s soothing voice echoed through her mind: Follow your heart, Twilight Sparkle, and have faith in yourself.

She felt empty. Where a weighty numbness had one saturated her very bones, she now felt nothing. Nothing, in this case, was a profound experience.
The two mares still stood with hooves pressed to each other’s chests. Neither had even blinked in the last few minutes, and Rarity felt no inclination to turn away from the beaming princess in front of her. The only sound was their slow, even breathing.
“Wait,” Rarity said with a raised brow. “I can hear you breathing.”
“Ahh,” Luna replied. “I believe our time runs short, then. Stormcloud told me about this little ritual—something from griffon culture, he said—while trying to convince me that words were overrated. It seems he decided to make that point loud and clear, so to speak. I’m sorry it came to this, Lady Rarity. How are you feeling now?”
Luna’s hoof dropped to the ground, and Rarity followed suit. “Better. But I’m afraid to ask what’s going on. I know it must sound terribly selfish… I don’t think I’m ready to leave just yet.”
“Then be selfish. I wish I could give you more time.” Luna sank onto her haunches, the brightness in her eyes dimming. “But I am here at Stormcloud’s sufferance and there is a price to be paid for it. I’m afraid I must ask something of you.”
Rarity gasped, her trembling returning in an instant. “No, I can’t. Please don’t ask anything of me.” Her eyes were wide and framed with tension as Luna gave her a quizzical stare.
“I don’t understand.” Luna placed a hoof on Rarity’s shoulder. “You have had a difficult time, I know, but I hoped you might feel some joy in being able to help. Perhaps I have made a grave—”
“No!” Rarity cried out, then shied away, continuing in a small voice. “It would be wonderful to help you, but… I only seem to make things worse. Please don’t ask, Luna. I just couldn’t stand it right now.”
Rarity’s head hung low as silence fell between them. Her head raised slowly up when Luna spoke softly. “It would seem that I have made a grave error.” Once again, the princess’s hoof guided her chin upwards towards that warm smile. “But now I believe I understand. Would you listen to one last admission of mine, dearest Rarity?”
The unicorn gave a somber nod.
“I hate being put on a pedestal. Ponies look at me as if I can wave away their troubles and I can’t stand it. Even Celestia acts as if I’m the one that supposed to do something to make things right. You looked at me that way last night in your bedroom, but for some reason it felt different and I did not know why. Now, perhaps, I do.”
Rarity flinched as Luna’s hoof rose up, but as it touched the side of her face, she closed her eyes and nuzzled against it.
“You were struggling to hold yourself together after the nexus had taken so much out of you. You could not answer me when I asked how you were feeling, but you made it clear that there was something you wanted me to know. It was clear because I wanted it too. I recognised my own desires and I failed you terribly because let it cloud my judgement.”
At that, Rarity opened her eyes and met the princess’s stare silently.
“Yes, Rarity, I failed you. We have all failed you. Twilight, Splashdown, Thunderer, Silverlight, even Celestia, all heaped praise upon your strength of character, but none of them told you, did they?”
Luna’s hoof gently brushed away a tear as it rolled down Rarity’s face, but more soon came to replace it.
“It was you who insisted on investigating Twilight’s dream, and you who struggled on to help your friends when you became ill. You insisted on investigating Twilight’s missing book and almost bested Sonata face-to-face—which few ponies can boast. Splashdown told me what he said to you this morning. He was wrong. It was my pleasure to use your title, just as you seemed thrilled to stand beside me, even through those dreary meetings. It didn’t matter whether you understood me: it was enough that you listened. In return, I wanted you to feel heard and appreciated, but I should never have pressured you. You see, there are some places that even my sister’s grace cannot reach, so I look for the places where she casts only shadows—places I might feel useful.” Luna’s hoof slid down and tapped Rarity’s chest. “Today, that was here.”
Her cheeks a little flushed, Rarity examined the ground at her hooves closely. “I’m not sure what to say,” she said quietly. “It’s too much to take in. I just feel… tired.”
“Then say nothing. There is still something I must ask of you, but, might you permit me one more indulgence first?”
Rarity looked up to find Luna’s leg outstretched, openly inviting her into an embrace. She accepted without hesitation, pressing herself against the princess’s smooth coat. “Thank you,” she whispered, squeezing tightly.
“I have no idea what you mean,” Luna replied with a wry grin, rocking gently as she spoke into Rarity’s ear. “We were watching you on the mountain. Twilight was right: Stormcloud is not cured. His magic is being channelled into the thing controlling me and I need you to go to him and see if anything can be done.”
There was no answer, save for another squeeze and Rarity’s muzzle sinking deeper into Luna’s mane.
“I know you’re worried. I wish I there was another way, but it is how it is. At the very least, cutting off his horn again should buy us some time. I am sure he will agree if you ask it of him, and… I will feel better knowing you are out of harm’s way.”
“I want to help,” Rarity whispered. “I do. It’s just…”
“I know.” Luna pulled back far enough to plant a long, soft kiss on the top of Rarity’s head. “Celestia does this for me when she knows I feel low. I hope it imparts my admiration for you.” She smiled and giggled as Rarity tried to hide her blush with a hoof. “If I might offer some wisdom? When you stumble, dearest Rarity, know that it is not because you are weak, but because the load is too heavy. Let your friends carry some of it for you as you have for them... and me.”
Stormcloud cleared his throat and the mares parted sharply, sitting side by side but staring in opposite directions. Both of them blushed. “Well, I’m glad to see you two are getting along nicely, but I’m afraid we’re almost out of time.”
Sitting beside Rarity’s real body, he gestured for her to join him. She took a long look a Luna before she did so, trotting over with a sheepish smile spreading across her face.
“I mean it. I’m glad you two finally managed to connect, but away from here things won’t be so easy. You’ll have to do all this again, and it’ll be harder. The me you’ll find up on the mountain will still be a crotchety old goat, and…” His voice dropped to a whisper. “Luna will be afraid to open up to you again. Being here is a bit like cheating.”
Rarity darted in to give him a quick peck on the cheek. “Then thank you… for letting me cheat. I think I’m ready now.”
“No,” Stormcloud replied with a sigh. “You’re not. But we believe in you.” The moment he finished speaking, the ghost of Rarity vanished.

“Are you ready?” Stormcloud asked, flopping back to the ground exactly where’s been before.
“Yes,” Twilight replied firmly.
“Good. I have nothing left to say, except that your friend is safe for now. You need not concern yourself with anything other than what is in front of you. Just say the word and I will release you from the dream.”
Twilight turned her attention from the speck of light in the sky and towards the stallion. “I was hoping to see Luna before then,” she said quietly.
“I’m sorry, Twilight. It was a risk to let her see your friend at all; if this conversation is discovered then we may lose the only chance we have at freeing Luna. I know you wouldn’t want to jeopardise that. You’ll see her when you succeed, as I know you will.”
Pushing herself up from her rump, Twilight stood up straight. “All right, do it.”

A brilliant flash of golden light doused the clearing as Princess Celestia appeared… inside a purple bubble.
Twilight dug her hooves into the earth, grimacing as her horn crackled and spat magic; Rainbow Dash, still clutching the unconscious Fluttershy, was snared in a golden aura as she plunged towards the ground; a streak of purple lightning slammed into Twilight’s shield, which cracked under the onslaught.
The shield flashed golden-yellow before a second arc stuck. This time, the flow was continuous, crashing against the bubble and cracking it again, but it held long enough for Twilight to finish what Celestia had started. Now snared in purple and gold, Rainbow Dash pulled out of her dive with several meters to spare as Celestia’s reinforced shield shattered.
Celestia, jaw clenched and eyes tight shut, appeared on the ground with a magical pop.
“Get Fluttershy back to Ponyville!” Twilight yelled over the fading hiss of lightning as Rainbow Dash swooped around in an erratic arc.
“I can’t just leave you all behind, Twilight!”
“Sure ya can, Rainbow!” Applejack shouted. “Keep ‘er safe!”
There was no more lightning. The yellow and blue blur wheeled across the sky one more time before diving below the treeline, but all eyes were already on the two princesses staring each other down.
“What have you done with my sister!”
While Luna cackled madly, Twilight rushed to her mentor’s side. “Princess! You need to leave!”
The laughter stopped abruptly. “No. You will remain here or I will torture these pathetic creatures until you come back.”
“Princess, please!” Celestia’s tight jawline relaxed as Twilight continued to shout. “I can do this! Please trust me!”
“Twilight Sparkle, my faithful student.” Her voice was measured, but with a bitter edge. “I cannot stand by and watch as this monster tries to hurt you to get to me.”
“Yesss.” Luna stretched out the hiss softly. “She will stay here with me, and the rest of you have one last chance to leave unharmed. You no longer matter!”
“Ah ain’t leavin’ the princess, an’ you gotta have hay-bales for brains if ya thought any of us ever would.”
“Fine,” Luna said nonchalantly. With a glow and hum, she released another barrage of magic, but Celestia shielded herself before it struck. The golden shield was smaller than Twilight’s, a focused disc that held despite the continual torrent of power crashing against it. Luna snarled and the lightning storm thickened, offshoots beginning to lick around the edge of the shield like living tendrils as more magic poured into the attack.
Twilight stared. Don’t try to overpower it, Stormcloud had said. Her shield wouldn’t hold for two seconds against such a spell. Unless…
“Applejack, back off,” she said, jumping towards Celestia. She didn’t look back. Side by side with her mentor, Twilight squeezed her eyes shut as her horn lit. An extra second of concentration was all it took to layer her shield behind Celestia’s. Against only that magic that spilled around the edges, her shield held, but it was already cracking.
“Twilight!” The din of lightning muffled Celestia’s cry, but there was something unfamiliar about it. Twilight lifted her head to see her mentor staring back, jaw clenched and a pained look in her eyes. There was no crack in her mask this time: there was no mask at all.
Fear. You can’t lose Luna.
She reared up and threw her hooves around Celestia’s neck, an image of a broken and bloodied Celestia flashing through her mind.
Well I can’t lose you, either.
Her insides twisted and her eyes opened wide, burning white-hot as magic poured through her horn.
Unacceptable!
Her shield expanded by a few inches and the cracks started to reform. “Princess, there’s a plan! She’s only going to get stronger if you stay here,” she shouted. “I need you to trust me. I’ll get your sister back, I promise!”
“Twilight, I—”
“Go! Please!” Squeezing tightly, she felt the princess go limp.
“I’m sorry, Twilight,” Celestia said, the life draining from her voice. “Of course I trust you.” With a bright flare of golden light, the princess vanished.
The light in Twilight’s eyes went out and the shield cracked immediately. She leapt clear as the purple globe shattered around her, accompanied by a wrathful howl from Luna.
“I did it,” Twilight said weakly. “It was one of those days after…” She staggered sideways but quickly regained her balance. “Oooh, woozy…”
Then, she collapsed.