The night after the first Nightmare Night:

Celestia stood on the balcony, watching the little town on the distance. Even though it had been the day of the Summer Sun Celebration, the night air fluttered coldly against her coat and feathers. But she didn’t shiver. The night’s newest feature consisted of the dark forms that resembled an unicorn face, imprinted on the lunar soil. The turmoil inside her mind began once again. ‘I have to be sure’ She thought as her horn began to glow, faintly at first. It’s golden glimmer illuminating the dark and troubling lonely balcony.

She cast the spell again. And again. Celestia methodically did it every few minutes, even though she knew the outcome. Once again, she felt her sister's presence in the long distance.

Celestia breathed a sigh of relief. Nightmare Moon was indeed sealed away.

'But that raises the question...' The Sun Princess thought to herself as her mind shifted upon a different subject. She looked back towards the interior of her room 'Who or what are those two?' She slowly walked towards the sleeping foals and stood besides both, curiously eyeing both. She pondered for a few moments; her sister had tried to cast spells to counter the Elements, but ultimately could not muster any defense after the blow had already connected. Celestia knew of no spells that could create something as complex as a pony in mere seconds, and she doubted that Luna did either.

Her mind went over the various possibilities as she trotted back inside the castle and navigated the halls; heading nowhere in particular. Just trying to shed some light into her restless thoughts.

They awoke in unison. Both yawned and, after looking at their surroundings, their eyes met for the first time. Both stood still for a long time before the filly raised her hoof and clumsily shook it in a welcoming wave. The colt raised his own and mimicked his sister. Both smiled a genuine, content smile. They found happiness inside the simple fact that the other existed.

Both foals quivered in fear and ducked in their respective blankets as the door suddenly opened with a loud thud. Celestia slowly walked in; her little stroll through the palace’s gardens proved itself uneventful. The foals looked up at the majestic Alicorn. The sudden fear that washed over them was now completely gone; replaced with sheer amazement at the enormous sight before them. They quickly tried to get to their hooves, but faltered and ended up falling over in unison, eliciting a chuckle from the royal pony.

"It is alright little ones. You need not fear me." She gently took a step forward. Fear washed them over one more time, as both foals took a step back in response to Celestia’s advance. She frowned and said: "Is something wrong, little ones?"

They both looked to each other. Neither of them said a word but they both knew what the other was thinking. Something about this pony made them both... afraid.

"Is something the matter?" Celestia's concern and regal voice caused them both to step back farther. The little colt unfurled his winds and assumed an instinctual defensive stance.

'This isn't going anywhere...' She thought. ‘I don’t think they understand me…’ She knew it was to no avail, but something compelled Celestia to try one more time.

"Can either of you speak? Can you tell me your names?" Both of them looked at each other.

Their faces scrunched up, their lips moved as though trying to force the words out.

"S- Sp-... Speak?" Said the colt.

"Na-... Names?" Said the filly.

Celestia contained her excitement in order not to startle the little foals. "Yes, my little ponies. Your names. What do you call yourselves?" The colt put a hoof under his chin. He looked as though he was trying to say something, but couldn't remember the words. The filly however began to wave her hoof around frantically. The colt looked at her for a second before his eyes shot wide open. He then began to do the same. Celestia looked at the two of them confused and amazed at the same time ‘They do understand me!’

"What is it?" Both of them waved their hooves in the air for a few minutes before they realized they weren't getting their message across. The colt put his hoof back under his chin while the filly simply tried again, growing increasingly frustrated.

Suddenly the colt's horn began to glow.

A flash of light.

A dark glimmer.

A small piece of parchment materialized itself in front of the little colt. His mouth slowly opened in shock. Celestia and the filly both gasped. Such advanced magic needed years to be fully mastered. Yet, this little ‘newborn’ colt was able to perform it flawlessly.

The colt's expression changed slowly from amazement to an excited smile.

He squeezed his eyes shut.

His horn glowed once more. He grunted as he tried once more to conjure another item into existence. Celestia could see the feint outline of what he was trying to make 'appear' but he couldn't conjure it into existence like he had the paper.

He sighed in frustration.

The filly grabbed the parchment that now stood next to her hoof and looked down from the paper to Celestia and then down to the paper once more. She put her other hoof over the paper and began waving it again; a slight frustrated appearance on her face. It then dawned on Celestia exactly what she was being asked. She darted out the room and down the hall to her own room. Both foals cowered at the Sun Princess’ sudden movement, but when she left the room they looked at each other in confusion. Seconds passed before Celestia returned with an ink well and a fancy quill.

Both foal’s eyes widened as they started to excitedly hop around the room. Their happy ecstasy elicited an amused giggle from Celestia.

Suddenly the filly's horn began to glow. A dark aura lifted the quill and clumsily dipped it into the ink-well. She looked on in amazement at the floating quill, not caring that little ink drops splattered across the floor. She put a hoof to her head, and seemed surprised that she was the one controlling it. The filly levitated the quill from the ink-well and brought it near the piece of parchment.

Celestia was amazed. Few foals displayed magical abilities at such an age. Especially without any kind of training.

The filly began to write, slowly but carefully. She obviously struggled keeping the quill in the air, panting with each drawn line. After a few minutes of writing, she levitated it to the side and dropped it to the floor, ink leaking out. She rubbed her head and breathed a sigh of relief.

The colt seemed confused as to what the filly had just done. He looked to her, and she waved her hooves around. The colt nodded and waved his own hoof around.

'It's as if they have their own little language... how cute.' Celestia thought. She allowed herself to take part in the foalish joy both were having.

The colt looked towards the pen and closed his eyes. He furrowed his brows as he tried to concentrate. A grey aura surrounded the quill as it, shakily, rose from the ground. Celestia was once again, mesmerized. The quill began to falter as the colt struggled to control his newfound magic. The filly franticly waved her hooves in the air, as if trying to convey another message.

Suddenly, the quill stopped shaking and the colt calmed himself. The quil fell to the paper and the colt began to write. Like the filly, the colt wrote meticulously. When he was done, the colt lifted the quill to the side and it dropped inelegantly to the floor. By now, the floor that stood around the paper was covered with small black dots. Something about the sight brought a smile to Celestia's face. A golden aura enveloped the parchment as she levitated the it with her own magic, lifting it up to her face to read.

It was an inky mess. Something that could be expected from foals who had never, ever written before. Celestia could barely make out the words on the parchment.

Nightshade

Nightshadow

"Are these your names, little ones?" Both of them wearily shook their heads in unison... and smiled. 'What odd names for young foals like you.' She thought to herself.

"Well it's nice to meet you both. My name is Celestia, but you can call me Tia." Her face suddenly drooped. She hadn't realized what she said until she had said it.

'Luna always called me Tia...' Celestia’s eyes filled with tears, but the Sun Princess mustered her all in order to stop the incoming downpour.

The two foals looked confused at the sudden change in her expression. She suddenly remembered where she was and shook her head, putting her smile back on.

"Are you two hungry? I haven't seen you eat yet." Both of their stomachs growled, answering her question.

"Yes!" They both answered in unison, eliciting another chuckle from Celestia.

"Alright then, come along. I'm sure the chefs could put something together for you." Celestia smiled as she walked down the hall, the two foals trotting slowly behind her. They looked around themselves, mesmerizing with every aspect of the large castle corridors. Everything seemed new to these foals.

'I'm not sure what you are, little ones, but Nightmare you are not.'

Two weeks later:

The two foals were kept in the castle in secrecy, the only ponies even knowing they exist being Celestia and her personal staff. She wasn't as worried about them being Nightmare Moon, but she was very worried about the citizen's reaction to the two. The Nightmare fiasco still had everypony in Equestria scared. Celestia recalled an incident a few days ago where a black coated pony was thought to have been a disguised Nightmare Moon simply due to her coat and light blue eyes. Celestia herself had to come to stop them from burning the poor mare alive.

In the relatively short time they had been together, Celestia had learned much about the two. They could understand Equestrian, and while they couldn't speak it very well at first, they had improved over time. The two of them seemed to know some basic things, like that the world they lived in was Equestria, but didn't have any other memories besides their names. At least, none they wished to share. They were nocturnal in their sleeping habits, something Celestia had wanted to change at first, but, after a few failed attempts, decided it was probably for the best. If anything it made it easier for her to spend time with them.

Nightshadow was quiet, but courageous and understanding. He was also very strong for his age. Once, an uninformed guard had attempted to apprehend his sister. Celestia had heard the guard screaming as he was sent down the hall, flying through the door leading to the guest room before landing with a loud thud.

Nightshade was vocal, intelligent, and seemed very eager to learn about any kind of magic. Celestia had refused to teach her anything beyond a proper telekinesis spell, but she seemed to get bored with just that quite easily. That was another thing about Nightshade, she got bored very easily. One of her pastimes involved pranking the guards and staff, often having Nightshadow lead them into various traps rigged with pastries or water buckets, or a simple tripwire. They were harmless, but Celestia resigned herself to finding something else for Shade to focus on before the staff became too annoyed with her pranks.

Celestia found herself immersed deeply in her thoughts. The little foals were quiet for the time being, always admiring the castle’s extravagant décor. The only sound heard was one of the Alicorn’s hoofsteps, which echoed through the marble floor.

'Perhaps I could teach her magic... I haven't had a pupil in ages...'

"Where are we going today, Tia?" Shade asked as they trotted through the hall; shattering Celestia’s trance. The little foals trotted quickly, maintaining their pace with the Sun Princess. She smiled a motherly smile at the little filly bouncing beside her.

"Well, today we are going to go run a few tests..." Nightshade gave her a confused look.

"What's a test?"

Celestia thought for a moment before answering. "A test is something you take to learn about something else." She said plainly.

Nightshadow tilted his head sideways. "What are we going to learn today?"

"It's... a surprise." The truth was that Celestia had been putting this off for a while. She had to be sure that they weren't a danger to other ponies first. That and she had to get used to being the Princess of both Night and Day. Ruling Equestria twenty-four seven left little time for personal matters, but Celestia was a smart pony. She could manage it.

It had kept her distracted from thinking about her sister.

They found their way to Celestia's quarters, where the first VIP she would be meeting today was waiting. He smiled as the three entered the room.

"Hello your majesty! It is great to see you in good health! And I see you have brought friends!" Celestia chuckled at the royal doctor's over-enthusiasm. She had known his name once, but he had insisted that she call him Doc for the sake of formality.

"Hello again Doctor. And yes I do have some friends with me this time. I was wondering if you could take a look at them for me?" Doc looked over the two. If he was surprised they were Alicorns, or shocked by their appearance, he did a pretty good job of hiding it from Celestia.

"Why, hello there little ones!” He said and waved a friendly hoof towards the two. “Why don't you come over here so we can get started?" They both looked towards Celestia who gave a curt, reassuring nod. They trotted over to the doctor pony, Shade doing her best to conceal her fear. She was actually quite introverted, despite her outspoken nature.

"Is it alright if I leave them with you, Doctor? I have some business in another part of the castle that requires my attention."

The doctor only nodded in response; all his mind was now analyzing both foals. Both Shade and Shadow shot worried looks at Celestia, to which she simply grinned.

"Don't be scared, little ones, if you need me I won’t be far." She trotted out of the room and down the hall. Her legs automatically took her to her needed destination as her mind wandered in memories. She reached a large wooden door. Gold hinges secured it firmly in its place. Celestia took a deep breath and magically opened the door.

"Princess Celestia! It has been so long dear!" She smiled at the old unicorn stallion before her. The large wooden door behind her slowly came to a close by itself.

"Hello Prince Greymane. I wish this was just a social call, but I need your help with something." The prince cordially bowed.

"Of course, my Princess. Though I must ask, what could you possibly need this old pony for?" He said, raising one brow.

"Despite what others may think, age has done you some good, I think.  You are an expert in divination and... spells of the mind, correct?"

Greymane feigned a gasp. "Could the Sun Princess, the most magically adept pony in all of Equestria, be asking me for magical help?" She gave him a stern look, which soon collapsed into laughter, shared between the two. "Alright then Celly, what do you need?"

She donned a serious look again. "Tell me Greymane... have you heard the rumors?

"Which ones? The one where Luna turned into a ghost and is haunting the castle? Or the one where Nightmare Moon ate the real Celestia and took her place?" He laughed again. Celestia was about to speak again when a light rapping was heard at the door. Greymane stretched his neck to look past Celestia, as she turned around to see the source of the sound.

"Um... Tia? The Doctor pony said that we should come get you?" Shade yelled through the door.

"Alright Nightshade, tell him I'll be right there!" They heard the sound of the echoing hoofsteps fading away. Celestia turned around once more to face Greymane.

"She called you Tia." He said, his usual bubbly demeanor now gone. "Alright, Celly, spill it. The only one who you ever let call you Tia before was... what's going on Celestia?"

Celestia wearily sighed. Greymane had poked her still oozing wound at the mention of her sister. She hung her head as she told him her story. About what she found after Luna's banishment. About what she learned. Greymane folded his arms and stood still, paying attention as the Sun Princess relayed to him everything that had happened.

"I'm confident that neither of them truly are Nightmare Moon... but I'm not so sure I can trust my judgment on this... that is why I called for you today." She said, as her hung head shook from side to side.

"You want me to... explore their minds?" Celestia lifted her head and looked deeply into Greymane’s eyes.

"Yes."

Greymane bit his lower lip. "You do realize that mind-magic is still experimental, right?" Celestia nodded. "And you still want me to do this?" She nodded again, making Greymane shift uneasily. "Well then... bring them in here and I'll see what I can tell you."

Celestia trotted back to the Doctor’s room. She opened the door and smiled when she saw the foals playing with some of his tools while the Doc calmly read a book. He looked up at Celestia. While he did smile, for a moment he flashed her an all too familiar glare, the one she usually got when she had been neglecting something about her own personal health, which happened quite often considering her job.

"Little ones, Mister Greymane down the hall wants to have a chat with you. He's going to run a few more tests and then we'll be done for the night, OK?" Celestia said, nuzzling one of the foals. They both sighed in unison and nodded as they ran off towards Greymane's room. Before she could react, Doc was in her face. If anypony else had ever done what he did next they would have been banished from Equestria on the spot.

"What were you thinking not telling me about them? I almost had a heart attack when they walked in!"

"I'm sorry! I just didn't want word to get out about them! I can trust you to keep a secret, right?"

"Well, yes of course, but the least you could have done is prepared me for them! You wouldn't need to put it in your letter, just say something like, oh, I don't know, 'I have two miniature Nightmare Moon's for you to look at!' Instead of just leaving me here with them like that!" Celestia frowned and looked towards the floor. The doctor pony relented.

"I'm sorry Celestia. I was just... surprised. They weren't any trouble. If it helps any, they are remarkably healthy! I can't say the same for every foal that I meet..."

Celestia then remembered something. "Did you bring what I asked you to?"

Doc rubbed the back of his head, trying to remember what she was talking about before smiling. "Oh yes, I forgot about that." He pulled a dusty, worn-out book out of his saddlebag.

"The compendium of Royal Health Records. Goes back to the time when medicine was still considered childish!" He paused for a moment and lifted his gaze from the book to meet Celesia’s eyes. "What did you need this for, anyway?"

"Oh nothing" She expertly lied. "I just decided that I want to add it to the library, instead of hiding it away for no reason."

Doc considered her words for a moment before shrugging and handing the book to her with his magic. She gripped it in her own and felt it before teleported it into her room, where she would read it later.

"Doctor, I appreciate the help and your... discretion in this matter." She smiled kindly to him.

Doc bowed. "The pleasure was all mine. Would you like me to leave a copy of their checkup list by your door, as always?"

Celestia smiled warmly. "Yes, doctor that would be wonderful. Thank you, but for now I must bid you a good night."

"Have a good night's sleep Princess!"

Greymane approached Celestia in the hall after she left.

"Where are they?" She asked him.

"Asleep. The spell tires the mind and the body." He replied calmly. Greymane himself looked tired. He rubbed a hoof on his eyes before adding in a whisper: "We need to talk... I found something."

The present day:

Nightshadow watched the familiar rainbow streak as it flew below.

'Her again…' He had just barely managed to avoid her crashing into him when he first walked into Ponyville with his sister. If they hadn't been invisible at the time, they would have been easily spotted.

Every day she would do tricks in the air, simply fly about, play pranks on other ponies, and usually crash into something before the end of the day. He usually watched her, sometimes her antics were quite fun, and sometimes other ponies would come to watch. Sometimes the unicorn mare would come to watch as well.

She flew around the town at breakneck speed. It didn’t impress Shadow by any means. He was faster than her; even when the situation didn’t call for speed. But this mare had him puzzled. How a regular Pegasus could fly so fast, he would never know.

"Came to watch the show today, brother?" Nightshade whispered into his ear.

Shadow wasn’t startled by his sister’s sudden appearance, but was confused by her question. "Show?"

She giggled. "You'll see." As quick as she came, Shadow could no longer sense his sister’s presence near him. He simply shrugged and continued to watch the cyan Pegasus’ antics.

The mare did flips, nose-dives, barrel rolls and various other tricks, never slowing down once... which lead her to crash through a window into an abandoned cottage on the outskirts of the small town. Nightshadow barely contained his laughter. He knew she wouldn't be hurt, she never was.

He then noticed something no pony else could.

A faint blue outline following the mare through the window.

Rainbow Dash rubbed her leg where she impacted the wall. She had a few cuts and bruises, but nothing serious. She flapped her wings a few times, lifting a small cloud of dust from herself and from the floor. 'A little sore, but I can't let that get in the way!' She was about to take off again when an ominous laughter suddenly filled the air. The laugher kept on, reverberating into the wooden boards that surrounded Rainbow Dash. Her heart began to race at this unusual happening.

A bright light suddenly shone from the other end of the room.

"He- Hello?" Rainbow asked, trembling; the adrenaline jolt set her on Fight or Flight mode. The laughter returned, more sardonic than before. Rainbow Dash fought her instincts and asked: "What's so funny?!"

"You."  The light shot itself towards Rainbow, faster than anypony could react. “Let’s play a little game...”

The rainbow streak shot out of the house, flying faster than before, faster than Nightshadow had ever seen. He had witnessed the Pegasus breaking the sound barrier, and thought at first that perhaps she was trying to do it again. ‘Something is... wrong’

He cast a light telepathy spell, allowing him to 'feel' the thoughts and emotions of the ponies below. He narrowed the range of the spell to the Pegasus. Her thoughts were frantic, her mind a mess, but one thought stood out amongst the others.

'WHY CAN’T I STOP?'

Nightshadow sighed. He recognized the spell now, and knew there was nothing he could do. He would have to wait until his sister had her fun. He felt sorry for the cyan Pegasus.

She flew through the library window and exited through the wall, leaving a trail of books and pages and small Pegasus-shaped hole behind. Shadow was able to see the lavender mare walking out of the library to berate her friend. When the Pegasus shouted something back at her, her face turned from anger to worry. She ran back inside the library and came back levitating a book. She frantically read through its pages while she galloped, looking for something to slow the rainbow mare down as she crashed through market stalls and buildings.

The lavender unicorn shrieked when the book suddenly jolted into the air. It turned from brown, to purple before melting and falling to the ground in a pool of sludge.

Nightshadow heard his sister's laughter behind him.

"Sister, I believe you've done enough for one day." He said in an annoyed tone. Watching the cyan Pegasus day after day wasn’t what he would consider fun. But it was better than standing still in the clouds all day.

"Whaaaat? It was just a little prank!" She said, faking an innocent smile. Her eyes followed closely the rainbow streak as the dark glimmer on her horn stood strong.

"Shade..."

"Hmmpf. You’re no fun." She giggled. The rainbow streak suddenly stopped and launched itself towards another direction. Towards the Everfree Forest.

"What are you doing?" Nightshadow stared at Shade as she directed the mare with her magic.

"You know full well I can't just end the show like that! There needs to be a... finale." She said; a twisted, devious smile erupted on her face at the mention of the last word. The rainbow streak reached the center of the forest and subtly changed its direction, shooting straight upwards. The entire town of Ponyville could see her fast ascent.

Her wings burst into flames. Nightshadow winced as Nightshade erupted into a hearty guffaw. The aura around Shade’s horn ceased and the cyan Pegasus started to slow down. The mare screamed as she plummeted to the ground, a plume of smoke following her down.

Nightshade kept laughing. "So, what do you think, brother?" She turned to face her brother, but he was gone, a small black streak taking his place for a split second before disappearing as well.