Chapter 1 - Twilight

Twilight Sparkle cringed in front of her liege and mentor as the alicorn princess lambasted her. She was on the carpet, both literally and figuratively, directly in front of the throne. The Princess of the Sun's eyes were flaring as if about to blast her with solar flames, and her voice was close to doing the job already.

"You call this a Friendship report? You were sent to Ponyville to learn and study important things, things vital to the safety of Equestria, and all I get are puerile homilies, worthless restatements of things every-pony knows, every pony that isn't a socially inept recluse! You have failed me utterly with this trash!"

A wrapped scroll of paper that had been held in her telekinetic grip suddenly flared and vanished in a blaze of flame that was so hot it didn't even leave ashes.

"I've spent too much time on this, this idiocy! Consider your mission in Ponyville terminated immediately. I should do the same to you, or at least send you to a prison on the moon to properly reflect on your crimes, but I think instead I should send you to a place of learning more suited to your level of skill! Guards, take her back to magic kindergarten!"

"Nooo! Princess, please!" Twilight Sparkle managed to gasp out as two larger than life Royal guards with glowing white eyes hauled her up by the shoulders. Suddenly they vanished in twin blasts of moonlight.

"Stop! Thou art not my dear sister, thou unclean shade!" As Twilight Sparkle slumped down, a dark winged form flew over her to stand between her and Princess Celestia.

"Princess Luna? I don't…" Twilight Sparkle was still too stunned to process what had just happened.

"Don't interfere, little sister, or would you like to spend another thousand years on the moon?" The white alicorn gave an evil grin that looked utterly out of place on her.

"Thou no longer hast the Elements of Harmony, and if you did, they would avail you not, for you have no love or friendship in your heart to power them!"

Princess Luna glanced back at Twilight. "Think! Would mine dear sister ever treat thee in this shameful manner? If thy work were insufficient, she would give whatever aid thou required to improve it, not dismiss you thus."

It hit Twilight like a flowerpot, followed by and anvil, a cart and a piano. Princess Luna was right! This couldn't be Princess Celestia, which meant… "A changeling! Queen Chrysalis?"

Luna was suddenly blasted backwards into a pillar by a solar flare that emerged from Princess Celestia's horn. "ENOUGH! I AM PRINCESS CELESTIA, SOLAR INVICTUS! YOU WILL BOTH PAY FOR THIS INSOLENCE!"

Twilight thought rapidly as she got to her feet. If Chrysalis had replaced Princess Celestia, what pony's love would she be stealing? The answer was easy; the whole kingdom loved their princess… This was very extremely not good. "She must be consuming the love of every pony in Equestria! How can we defeat her?"

She dodged out of the way as a blast of solar power incinerated the carpet she'd been standing on and left a deep crater in the stone flags underneath.

Luna's voice came back, weak and in pain, but still unconquered. "You are the Element of Magic, and my elder sister's favourite student, and your love for her goes beyond most any-pony else's. You alone may be able to strip the power this charlatan has stolen away."

Twilight was suddenly bathed in light, but this was not the heat of a solar flare. Instead a cool wash of moonlight enveloped her. "I give you my love for my sister, and grant you my power, so that you may defeat this evil!"

Twilight felt amazing, as if every pore in her body was overflowing with power. Another solar flare hit her but splashed, pushing her back before she dug her hooves in. She flared out wings which she hadn't realised she had and lowered her horn, which felt like it had grown a hoof in length. "You have hurt Princess Luna, and kidnapped Princess Celestia! You aren't her, you never will be her! Now give her back!"

Her failsafe spell, designed to cancel any enchantment or magical effect blasted forth at the false Princess who defended herself with a beam of solar energy. However Twilight's spell was empowered by an alicorn's power levels and all the love for her mentor she could muster. The fake's expression became one of anger, and then fear as the he two powers duelled and Twilight pushed her solar beam steadily back.

However, her spell stopped only a few hooves from the other's horn, the two forces forming parabolic fans of power that splashed and sprayed away from the meeting point. The false Princess Celestia lost her look of terror and gave an evil laugh.

"Why… why isn't it working?" Twilight gasped.

She heard Princess Luna's voice. "In your heart of hearts, there is still a shadow of doubt that Princess Celestia truly believes you worthy of her patronage, that she might do such terrible things if you failed her. This thing used that against you, and now it is the only thing blocking you from defeating it utterly. You must face that fear, defeat it, and only then will you defeat this creature."

"I know she wouldn't…" Twilight's failsafe beam was pushed back a hoof. She gritted her teeth and pushed, not outwards but inwards. Words weren't enough, especially when in her heart of hearts she knew they weren't true. There was a part of her that worried that the Princess _would_ punish her if she failed or made some terrible mistake.

Celestia was an immortal alicorn with thousands of years of wisdom, while she was just a regular unicorn. Princess Celestia must have mentored hundreds like her, unicorns far more powerful and far wiser than she was. She'd chosen Twilight, given her care and attention, but what if Twilight couldn't deliver in return? She'd been given tasks of great importance, if she failed in some way, ponies, the whole of Equestria could be hurt. She'd deserve to be punished…

As her introspection got more and more frantic, her beam had been pushed back further, but now it held steady as she had an epiphany. Yes, Princess Celestia had known all those great and powerful unicorns, even mortal alicorns like Princess Cadence, but she had chosen _Twilight_ as her student, to carry on that tradition. She had millennia of experience, so she must know something about picking correctly.

Ultimately, she believed Twilight _could_ handle the tasks she required of her. It was Twilight herself who doubted. She was the one who imagined such horrible fates, because she felt the stakes were so high. But of the two, Princess Celestia had the experience, and the knowledge to decide what she could and couldn't handle. She wanted Twilight to succeed, to learn, as Princess Luna had said. As long as Twilight did her best, even if she made mistakes, Princess Celestia would help her to overcome them, not punish her.

Her eyes opened, and the force projecting from her horn redoubled, forcing the solar beam back once more. "Princess Celestia expects great things from me, but she would always help me accomplish them! She believes in me, and now, I believe in her."

She started walking forward up the lower ramp leading to the throne, the energy streaming from her horn pushing her opponent's attack back. "You are nothing like her, no matter what form you hide behind! I love her without limit, and I will do whatever it takes to help her!"

The fake Celestia's eyes widened. "No! No! It can't be possible…"

The tiara of the Element of Magic appeared on Twilight's head, and her eyes whited out as her spell blasted forward and shattered her foe's final desperate defence. It engulfed the fake Princess with a sudden flash, and left nothing but a fading shriek and a cloud of dark smoke that evaporated away.

"I… I destroyed her?" Twilight suddenly felt sick, Chrysalis may have been an utterly evil parasite, but she was a living creature, not some echo created by a mirror pool. She collapsed to her knees, staring at the throne. The crimson carpet that lead up to it had been burned away in the battle, and reflection that stared back at her from the metal ramp underneath was that of a purple alicorn, similar in size to Luna. "I only meant to strip her of her powers, banish her…"

"That you did." Luna came up alongside her, and laid a wing across her shoulders. Twilight shifted back to her normal unicorn form, but the Princess's benediction was not just a way to recover her power. Her wing curled over Twilight in a hug. "However, it was not a changeling you faced, but a nightmare."

"A nightmare? But that means…. This is a dream?" She instinctively looked around, trying to feel the difference, and as often happened when you realised you were in a dream, it started to fade.

"Yes, but more than just a dream!" Luna called out. "It is a threat to all of Equestria, and one that will need your skills!"

She was fading with the dream, but her final words were, "Cast a sleeping spell when you awake, that I may explain…"

Twilight suddenly jerked awake, finding herself in her bed at Golden Oaks library. Her bedclothes were all tangled up, and she was sweating. "Whoa! I really need to stop snacking when I pull a late night study session."

She looked out of the window at the moon. Had Luna's presence been real, or just another part of her dream? She'd learned about Luna's ability to dream-walk after that Nightmare Night, when she'd decided to find out whatever she could about the restored Princess. There weren't many records, but one of her secondary titles was the Guardian of Dreams. That was clearly exactly what she'd done in Twilight's case.

Looking back on it, she should have realised it wasn't real. Princess Celestia, talking about executing her over a bad friendship report? The nightmare had really gone over the top there, but one of the things about dreams was that when you were in them, you accepted the craziest things as reality. But how could a nightmare, however horrid, be a threat to Equestria?

A shadow flickered across the moon, the outline of a pony's head in profile, and a familiar profile at that. That decided her course of action, doing as the Princess had asked, seemed the best way to find out was to do exactly what was going on. A sleep spell would only work for a few minutes, but if the body was ready for it, natural sleep would take over after that, and while the spell was in effect even knowing she was dreaming wouldn't wake her. That should be long enough…

A whimpering from the direction of Spike's bed caught her attention. So she wasn't the only one who'd had a nightmare. For a moment, she considered waking him up, but decided that it was as easy to tell Princess Luna about it when she saw her again, and get her to do something about it from inside the dream. She tucked herself back down between the covers, and cast the sleep spell. Her eyes grew heavy, and her mind grew fuzzy.

When she found herself thinking clearly again, she was in a featureless grey mist. A figure loomed in front of her, and resolved itself into the Princess. "Come, Twilight Sparkle! There is much for you to learn."

Twilight wasn't sure exactly how she was doing it, but she followed the Princess and found herself on a balcony, looking out over a grey plain with craters and brilliant rays of splash debris. Worn and eroded mountain peaks peeked over the horizon while above, the stars were brilliant and unwinking, glorious beyond even the clearest night sky.

The balcony had multiple telescopes, of a size and quality that made her drool. All of them were pointed in the direction of a globe that was gloriously marbled in blue and white. She realised that had to be Equestria, as they must be on the moon. This made her stop and look around again. She was on the moon! This must be part of the dream, but considering who had created this dream, the details were probably accurate.

"My Night Palace," Luna said, smiling. "This is my watchtower, and my keep, from which I observe the dream realm."

Supressing the part of her that wanted to sqeee and bounce up and down like a little filly, Twilight turned to see the palace itself. The balcony projected from a faceted tower of ebony stone and purple crystal that speared up from the surface far below. It was surmounted by many angular spires, with graceful flying buttresses and bridges that arced between them. Waterfalls of silvery liquid flowed down through pools and viaducts that flowed throughout the structure. It was not the white splendour of Canterlot, but it had its own majesty and beauty.

"Come, we have much to do! Time in the dream realm is not that of the real world, but even my powers can not stretch this moment forever." Luna led her inside the palace, through elegant but spartan chambers and across high, narrow walkways that lay between neighbouring towers.

They entered a large chamber that was equal parts study, workshop and laboratory. Star charts covered one wall, in front of a vast draftsman's bench, and other deeper parts had arrays of alchemical equipment through which more of the silvery liquid bubbled and fumed. However, the central section was devoted to magical studies.

Free standing bookshelves carried ancient tomes and racks of scrolls, while others lay open but stacked up haphazardly on the many benches and tables that lay scattered through the area. Magical devices and instruments of manifold uses also rested amongst them. Twilight found that she was again drooling, and quickly wiped her mouth.

Her distraction quickly came to an end as they reached the centre, and a magic circle that was the mystical equivalent of six feet of force-field jacketed, case hardened neutronium armour plate. Suspended within it was a smoky figure, vaguely equine, with glowing purple eye-slits as its only feature.

Twilight hadn't gotten to be Princess Celestia's protege by being slow on the uptake. "A nightmare?… wait, nightmares have an independent physical form?"

"Yes and no." Princess Luna answered, her magic lifting one of the bulkier pieces of equipment, a thing of eye-pieces and lenses, and using it to examine the creature. "Nightmares are created within a pony when some bad though or feeling expresses itself within their dreams. It had no independent existence. My job is to help them resolve the nightmare, either by helping them to see that their fears are groundless, as I did with you, or if their fear has a genuine cause, convincing them to resolve that cause in the real world.

"But this, this is something I have never seen in all my eons as a guardian. Hundreds of them, thousands have flooded the land. They seek a sleeping pony's mind, and invade it, using what they find there to bring to life their worst possible nightmare…"

"Spike!" Twilight's eyes widened as she remembered what she'd seen. "Princess, Spike has been affected, we have to go help him!"

The Princess's voice stopped her in her tracks as she turned to go. "Hold! We shall help him, and all the others so afflicted, but you have more to learn before you can do so effectively. Did you wake him?"

"No, maybe I should have…"

"It is as well you did not. From what I have discovered thus far, they feed on the suffering of their victims, and will simply lie dormant when the mind awakes, only to assault it again when sleep returns. Only if they are defeated will they be destroyed. As I told you, in this place I can stretch a single moment greatly, so I have ample time to prepare you to face this foe and defeat it."

"But Princess, surely you can do it yourself! You did for me."

"I have tried…" A touch of tiredness entered her voice, and for the first time Twilight really looked at Luna, rather than the Princess. She saw the alicorn's eyes were weary and her wings were drooping slightly, but then Luna straightened up and she wondered if she'd simply imagined it. "However, there are many of them, too many for me to handle alone, and I must also seek the source of these creatures, to stop more from spawning."

"I'll help however I can, but wouldn't Princess Celestia be more useful, or my big brother and Cadence? I would guess these things would be hurt or destroyed by daylight, and if they are creatures of fear, the magic of love and protection should banish them too. I'm only a regular unicorn."

She heard the chuckle in Luna's voice. "You are as quick witted as you are modest, Twilight. You are also wrong, you are anything _but_ a regular unicorn. My sister, Cadence and Shining Armour are already doing what they can. As I have the Night Palace, my sister has her Garden of Sunlight. She dwells there even now, and I have brought them both to her.

"They even now combine their magic in a spell of protection that extends the effect of her garden throughout the dream realm of Equestria. No Nightmare may essay that protection without being destroyed, so no new nightmares may infest the dreams of ponies. However, those already ensconced within a mind are protected, shielded.

"To destroy them, you must enter those ponies' nightmares and help them to fight whatever form that Nightmare has taken. But mark this well, it must ultimately be that pony themselves who defeats the Nightmare, or some remnant may remain, feeding off the residual fear until it can once more spring forth full blown."

"What if I wake up? What if they wake up? How do I…"

Luna held up a hoof, which stopped the flow of questions. "Fear not, I shall teach you the spells and disciplines that will allow you to remain in the dream realm, even knowing it for what it is, travel it at will, and to enter the dreams of others and aid them. This is a great power I entrust you with, and one that has great potential for misuse. However, my sister has faith in you, and I believe it is well founded."

She smiled. "I find it somewhat appropriate. After all, you are Twilight, the cusp between day and night, and it is only meet that you learn from us both."

Despite the seriousness of the situation, Twilight's eyes sparkled. It had been a great honour to receive training from Princess Celestia. However, to have Princess Luna train her as well, and in a whole new branch of magic… "I promise I'll be careful, only use it to help ponies!"

"Of that I am sure." Luna gave a small smile. "You may not be alone in your quest, it is possible that the bonds of friendship you have with the other Bearers of the Elements of Harmony will allow you to take them with you. They have proved adept at solving problems in the past, and as long as you impress upon them the gravity of the situation, I am willing to extend my trust to them."

Twilight gave a sigh of relief. She was glad this wasn't a solo test, if the task had strained the vitality and powers of an alicorn, it was not one she wanted to face alone. She examined the trapped Nightmare with a more critical eye, her analytical side coming to the fore. If she was going to fight these things, she needed to know as much about them as possible. They seemed to draw their sustenance from fear, which suggested something like a Windigo, but their natural form as a dark mist suggested another possibility.

"So what exactly is it? Some new form of Windigo? Some remnant of King Sombra, or Nightmare Moon…" she suddenly stuttered to a halt. "Oh my gosh! I'm sorry Princess!"

However, Princess Luna didn't seem affronted. "Do not worry, Twilight, I have made my peace with that part of my past. Nightmare Moon was a thing of evil and madness, lunacy, if you will. My own memories of that time are well, a nightmare, and my memories of her imprisonment here thankfully hazy. I am well rid of it, as I told you that Nightmare Night. Indeed, it occurs to me that I never actually thanked you for that."

"You said you couldn't be happier…"

"That is not the same thing. Know now that I owe you my deepest thanks. Without your dedication, your leadership of the other bearers, I would never have been reborn, and Nightmare Moon's insane scheme would have come to pass. Bring night eternal simply so she could show off the night sky? Ponies would have been too busy starving and freezing to death to appreciate it. But as I said, she was insane, unable to see the consequences of her actions."

"I did wonder about that, it never made sense…" Suddenly Twilight's brain connected a number of unrelated facts. One thousand years, the defeat of King Sombra who manifested as a black cloud, as did Nightmare Moon. "King Sombra cursed you as well as the crystal ponies! Even a speck of his horn was enough to corrupt the land within the Crystal Empire, he wanted you to destroy everything in vengeance for defeating him!"

Luna ducked her head in acknowledgement. "It is as you surmised. Though we ourselves did not fully realise that until the Crystal Empire reappeared. That same spell that banished it for a thousand years banished even the memory of it from most ponies, and even affected our own recollections.

"I remember more clearly now, while I was unhappy that so few ponies appreciated my night, it was hardly the sort of thing that would cause me to go insane with rage. I had my duties as Dream Guardian, and my other responsibilities for the Night Court. But after we faced Sombra, then my anger began to grow. That seed you spoke of must have latched onto my unhappiness and fed it, nurtured it until it blazed forth as…"

"Nightmare Moon! It all makes sense now! Do you think he knew Princess Celestia would seal her up for a thousand years the same way he was? Oh my gosh, he could have planned it that way so that when he re-emerged he'd have an ally! Maybe he just misjudged the timing slightly, or he didn't count on Princess Celestia finding replacement bearers for the Elements with you unable to assist her!"

Luna looked shocked. "That… is a disturbing thought. In truth, he was a fiendish opponent, with plans within plans and contingencies for everything. For all his power, Discord was far less subtle. Of course that same power meant he never needed to be."

Twilight turned back to the trapped Nightmare. "Well I'm fairly certain this isn't Discord's work. As you said, he isn't usually this subtle, and it's been months since he was turned back to stone. He'd never have set a plan in motion that would take this much time to mature. He had the patience and attitudes of a spoilt foal."

Luna shook her head. "And yet my sister believes he could be a force for great good if he could be made to see the error of his ways…"

"Like that could ever happen!" Twilight smirked, then realised that she'd just contradicted Princess Celestia. With a more thoughtful expression, she qualified her statement. "At least I don't see how it could."

"Nor I, truth be told. But my sister has always had a gentler heart than I." Luna shook her head, moving around to observe the Nightmare for herself. "I do not believe this is any part of Nightmare Moon either. I am more familiar with the foul magical essence of that creature than I ever want to be."

Her horn glowed and a number of instruments, all focussed on the magic circle, started to orbit her. "King Sombra, or some form of Windigo? Maybe even a fusion of the two? Tis possible the creatures found some remnant of his essence after the Crystal Heart shattered him, and consumed, or were consumed by it. I am less familiar with their thaumic signatures, so I can not be sure."

She moved to the big workbench, the instruments floating back to their resting places, and from one of the hundreds of cubbyholes took down a scroll that expanded as she brought it down. She unrolled it to reveal a beautifully detailed map of Equestria and its surroundings. "In light of that, it might be as well to patrol the frozen north first. The infestation has spread far and wide, but there was no pattern as to when and where it struck. If your surmise is right, there may be some clue to be found there."

She returned her attention to Twilight. "But first I must instruct you in the disciplines and duties of a Dream Guardian."

Twilight stood tall and looked into her eyes. "I'm ready. Princess."

The ancient alicorn, gave a small smile. "Call me Luna. Of the many ponies I have known, few have earned the right more fully than you. For myself, I look forward to calling you student."