In the comfort of Canterlot Castle, Princess Luna has been getting strange feelings from the Everfree Forest for the past week and decided to send out her shadows, Umbra and Gloam, to conduct a thorough investigation.

Five days in the Everfree Forest, the two shadows came across an old-looking cave in the very heart of the forest itself and quickly made their way back to Princess Luna who was anxiously awaiting any news.

She was perched atop the balcony where she and her sister, Princess Celestia, would occasionally sit and converse, overlooking the vast horizon. Umbra and Gloam silently crept out of the shadows and knelt before their Moonlight Mistress.

Princess Luna tapped her hoof in anticipation. "Well?" she asked loudly. "What have you two found out?"

Umbra stepped forward and kneeled again before speaking. "There is a cave located at the very heart of the Everfree Forest."

Princess Luna raised her eyebrow before settling on a slight scowl. "A cave?"

Gloam nodded slowly. "Yes, ma'am. To our knowledge, that cave is new, but it appeared to be there for ages."

Striding slowly towards the edge of the balcony, Princess Luna gazes at the Everfree Forest far off into the distance. "An old cave that suddenly just appeared out of nowhere?"

Umbra affirmed his Benevolent Mistress's inquiry. "Yes, ma'am. We didn't venture inside, but Gloam and I are certain that must the location of the disturbance."

"It feels heinous, yet tamed, like me," she whispered to herself. Princess Luna turns her strong gaze at her guards. "Sister could never feel anything like this unless she walked the path of darkness. And thus, I shall go alone. Step back into the darkness, my loyal servants, until you are summoned once more."

Gloam looked at Umbra and then back at Princess Luna. "Ma'am, with all due respect, I don't think this is something you should do by yourself."

Umbra nodded. "I agree. It might be dangerous."

A small, devilish grimace was strewn across Princess Luna's face. She raised her muzzle in the air and looked down at her guards with an air of vexation.

"Such imprudence my guards; how rude. Have my servants been around long enough to question my judgments so casually? Perhaps I let you two be a little bit too free-minded..."

Umbra and Gloam quickly prostrated themselves with their heads to the floor, offering forgiveness.

"N-no, ma'am," Gloam said worriedly.

"We apologize for our misplaced audacity," Umbra said, emulous in his partner's disposition, hoping to abate the wrath of their Azure Mistress.

The two shadows bowed before Princess Luna for stepping out of line. She chuckled and rolled her eyes.

"I was jesting. I admire your worry for my safety, it shows that even shadows like yourselves are capable of more than just tools to be dispensed on a whim. I am a princess of Equestria, so have some faith in your creator."

Gloam and Umbra, warmed by Princess Luna's words, trusted in her safety and disappeared into the darkness. The Moon Mistress was left to her lonesome.

"Good boys. Now time to investigate what's inside that cave in the Everfree Forest. Sister, please do not notice I am gone."

Princess Luna opened her wings and flew off into the night towards the daunting Everfree Forest. She lands at the entrance and takes a huge breath of fresh air as any in the forest would be foul.

Onwards she goes into the darkness, fighting against the various dangers of timber wolves, giant hawks, and bugbears. After hours of combat, Princess Luna finally found the cave in the Heart of the Everfree Fores tired and wounded; a sly timber wolf had slashed at her right wing.

Trotting slowly towards the cave, Princess Luna feels the pressure she felt up at Canterlot Castle, but this time it was heavy and made her body shiver. Despite the unnatural weight, she pressed on, determined to figure out who or what anomaly beckons. Using her horn, the moon-touched princess lights up her path.

Venturing inside the cave, Princess Luna felt the cold, soggy soil squelching with each hoof step; the walls of the cave were moist and clammy. Further in, across the inner walls, was a type of multi-colored luminescent liquid that slid from the walls and dripped from the ceiling. Observing the oddity, Princess Luna witnessed that if enough got into the soil, various lights would flare and shine, then flicker before darkness surrounded her. This was a repeated occurrence and Princess Luna had never seen anything like it before.

"What... is this place? I don't understand..." she muttered to herself aloud.

Awestruck to near silence, Princess Luna found herself looking at a large chamber or cavern lit up by white light with a large, ruined house sitting on the far side. The water that flowed was gray, the grass was red, and everything was gradually changing color every other minute.

Overwhelmed by the sheer magnitude of the landscape, curiosity pervaded within the princess and bade her forward in expressive disbelief. "How is this possible?" the Blue Princess wonders. "Who lives this deep? This is all such fantasy; none of this can't be real."

The more she looked the more she didn't realize how much closer she got to the large, decrepit house until she got to the front door. Vines and mysterious mossy growth were entangling the door; Princess Luna had never seen something so appalling, but what she felt lies just beyond the door, so she knocked with her good wing and idled, waiting for an answer.

As seconds pass by, the door became unhinged and opened very slightly, enough for Princess Luna to gingerly creak it open and pass through, yet no creature was behind the door to open it. Immediately after, Princess Luna felt a surge of magic and heat assaulting her, pouring through the door. Never before as such magic as violent or tame rushed through her celestial mane, and Princess Luna had gradually become fearful.

Forward she goes, the door slamming and locking itself behind her, startling the anxious princess. Her horn lit up, but the light only went around her body; the mass of darkness was simply too much, rendering the illumination spell near useless, but this did not deter Princess Luna from finding what's been causing this burdening pressure.

After what felt like an eternity in the darkness, a mood Princess Luna knew all too well, there was a distant light that appeared to be a large room with peculiar-looking spires, stalactites, hanging from the top and that's when she heard it. Princess Luna heard something breathe in front of her. She was stunned and curious.

"Who's there?" Princess Luna asked firmly. "Are you the one causing this?"

Princess Luna witnessed five slim black legs, similar to arachnids, stretch out of the darkness, and four shadow-like arms with long, protruding bony fingers surrounded Princess Luna. She saw rusted chains dragging across the ground and an old-looking stave grasped firmly in one of the four hands. The creature's face was hidden by a black cloak that covered most of its body. Princess Luna could see two shining blue eyes staring down at her body.

Princess Luna was in the presence of a creature of epic proportions, and she had no hope of fighting back if the creature were to attack.

"Well, look who sought me out from the safety of the castle." The creature's voice echoed and sounded like multiple people talking all at once. The volume shook Princess Luna down to the core, giving her a slight headache.

"I am-"

"I know who you are and what you have done," he said, cutting the princess off. "Princess Luna, younger sister of Princess Celestia and former villain Nightmare Moon. Out of spite and jealousy of your sister having the luxury of her citizens being awake during the day, you attempted to cast the entire land in an everlasting night."

Princess Luna couldn't believe how lucid the creature's knowledge of her past was. "How did you know that?"

The creature chortled. "I simply do, little filly. I have knowledge spanning from more than ten thousand years ago."

"Who are you and why can I feel you?"

The creature tapped the floor twice, sending a low rumble throughout the earth beneath the princess. "For one such as you, being attuned to darkness should have been clear."

Princess Luna glared at the creature. "Tell me your name."

"Yatava," he said slowly.

Princess Luna has encountered Yatava, a mysterious entity who claims to possess knowledge of Equestria and the center of a type of feeling or pressure Princess Luna is experiencing.

In the deepest heart of the Everfree Forest lies a cave that dwells a profound god among creatures and men, a being who has seen everything more of the past than anything else. He knows secrets not meant to be said, actions that go unpunished, the good and the bad, and yet he is indifferent towards them all.

The rightfully vainglorious god has awoken from his slumber for quite some time and now a fearful visitor anxiously stands before him. Indeed, Princess Luna felt his presence and sook him out hoping to get answers, but all she had so far was fear and paranoia.

Yatava claims to know over ten thousand years ago and he proved it by telling Princess Luna she was Nightmare Moon, a spiteful, envious pony who wanted no more than to shroud the entire land into the eternal night for her night was beautiful, but none would see it, leading her down a path of evil.

The two were talking with Princess Luna justifying herself. Arguing with Yatava, telling him she came back from banishment and was reformed, Princess Luna made it a personal mission to improve herself to become something more than a monster she used to be. To Yatava, once something had stridden down a road, there is no turning back no matter how hard one tries.

"It's interesting how a filly like yourself try so hard to change your ways, but the path of darkness has a lingering hold, and even if you turned away, darkness would always follow."

"That's not true!" Princess Luna stamped her hoof to affirm her conviction. "I give everything by serving Equestria. I am grateful to those who helped me, and yet you say all that doesn't matter. Lies!"

Yatava chortled, shaking the ground slightly in his mirth. "Yet here you are. Something deep down made you come here. It's a feeling of desire and want. Though you may believe the dark side of you has been purged, you would be sorely mistaken."

Princess Luna cautiously stepped back. "What... w-what do you mean?" She stammered.

Yatava pointed a black finger at Princess Luna's heart. "The other you want only what's best. You may have the body, but feelings and desires are blatant; a part of you still wants Equestria."

Princess Luna's heart vigorously started beating, propelling her to the ground coughing and trying to catch her breath. She started to sweat and yell as the pain began to arise.

"What's happening to me?!" she wailed.

Yatava chortled again. "Let me show you."

Yatava raised his large stave and tapped it on the ground, sending out a wave of magic that blasted through Princess Luna. Slowly, the right side of her face started to transform, her mane and coat became darker shades. Princess Luna was witnessing true horror as half of her face was Nightmare Moon's, who began to laugh crazily.

Princess Luna instantly became distressed. "No! How are you here?!"

"Fool!" Nightmare Moon roared at Princess Luna. "I never left! You may control the body, but I am with you until the day you die!"

"Formed from spite and envy, Nightmare Moon acts to be the gradual proliferation for your suppressed desire, the hidden thirst to rule Equestria as your own; she merely wants what's best for you."

Princess Luna denied Yatava's words by quickly, and painfully, shaking her head. "N-no! You're wrong!"

Nightmare Moon busted out laughing, filling the area around with the echoing voice. "Liar, prevaricator! Little Luna, your taste to rule Equestria is insatiable! You cannot disregard the truth!"

"Stop it!!!" the Moonlit Mistress shouted.

"You will never stop wanting Equestria! First, you wanted the night, but why stop there? Your feelings created me! I'm doing what you wanted, and here you are resisting me!"

"The temptation will always be quelled, yes, but it will never stop, nor will it ever go away." Yatava watched with an aura of relaxation.

The right side of Princess Luna's body became Nightmare Moon's, forcing the aching Princess to stand as she yelled out in misery. They both struggled to gain full control over the other in a battle of pure will.

"When will you let me take control?!" Nightmare Moon lambasted, her frustration gradually rising. "Let me give you want you secretly wanted all along!"

"Never!!!" she vehemently retorted.

"Infantile princess... Why do you resist the temptation?! Let it overtake you! Let it give you what you desperately yearn for! You crave Equestria and I can give it to you if you let me in! Never throw away what you want! You take it with your very hooves and make it your own! Why is this so difficult for you?!"

"I... I..." Princess Luna began to hesitate.

"Why do you suffer deep inside? If you let me in, the desire can be achieved, do you want that?! I don't understand! Why do you show such contempt towards me?! Why is it that you are content with not being the one to have it all?! Why?!"

The rapidly firing questions from Nightmare Moon sent Princess Luna into a state of reluctance as she slowly struggled to provide any answers.

Yatava wiggled his black fingers slowly. "It only takes a single plea to set the gears in motion."

He snapped his fingers and reality shifted. Princess Luna was in the castle. Both he, Princess Luna, and Nightmare Moon saw the glorious throne atop the small stairs beckoning for a ruler to set themselves upon it.

"You see it with no creature upon it. The throne is reserved for you, little filly. What will you do? Forgo your birthright or seize it for yourself. Choices, choices."

"It's right there!" Nightmare Moon yelled in excitement. "Ripe for the picking! This is your chance to seize what should have been yours!"

Princess Luna stared gravely at the throne, trying to turn her eyes away. "I... I can't..."

Nightmare Moon's eye glowered as her mood went sour. "Can't or won't?"

Princess Luna didn't provide an answer, but her silence was more than enough for Nightmare Moon.

"That's why I'm here, to make the hard decisions for you!"

"No!!!"

Princess Luna struggled to stop Nightmare Moon from bringing her closer to the throne. Princess Luna yelled and yelled, trying to pull away with all her might, but the temptation laying inside her started to take over as Nightmare Moon slowly inched the body closer and closer. The struggle went on for an hour until Princess Luna was standing right in front of the throne.

"It's right there! Take it! End your suffering! Touch it!" she bade Princess Luna eagerly.

"No! I can't!" Princess Luna, even with a muzzle away from the throne, desperately refused the growing temptation.

"Why can't you?!" Nightmare Moon roared with outrage. "Tell me why, Luna!"

Finally having enough of this flippant tug-of-war game, anger had reached its peak inside Princess Luna. "Because... I... Am... Not... Worthy!!!"

Princess Luna's glowed violently as a grand magic spell blows up the entire castle, taking her and Yatava back into actual reality. The warlock appears unaffected. Princess Luna stood, weeping and frustrated.

"What did you say?" Nightmare Moon asked softly, as if in shock.

Tears began to flow excessively from Princess Luna's eye. "I'm unworthy. I'm undeserving to rule. I wanted it all to myself. I wanted... I wanted it so bad that I created you! I didn't just want the night, I wanted everything, everything! But I failed. I lost what was important. When Twilight and her friends bested me, I was given a second chance for a do-over."

"You fool..."

"I lost sight of the job I was given and became desirous. To atone and to do what's was right, I tirelessly, day and night, strived to win over the hearts of my subjects I tormented. And you were right... those feelings never went away, not for a single second, but that's when I knew I wasn't worthy."

"Then why am I still here?"

"I denied your existence, but I never forgot. You are here to remind me that I will never be worthy, and in turn, you are worthless. Seeing you reminds me that we are worthless and unfit to rule. My sister is the leader, not me. I merely help her, nothing more."

"But... your desires. What about them?" Nightmare Moon was soft-spoken and distraught.

Princess Luna sniffled, continuing to cry. "They are useless to a pony that is unworthy. I am content that I can view the smiles from my subjects even when deep down I don't deserve it. I am here for my sister and dedicated to helping her make Equestria safer. I am so thankful... But it hurts... It hurts so much that I cry."

"All you ever wanted... I see. This body is yours."

"Nightmare?"

Nightmare Moon vanished, delving back inside Princess Luna, giving her full control of her body.

Princess Luna didn't understand. "What happened?"

"You are an interesting one," Yatava chimed in, wiping Princess Luna's tears with magic. "Though you are unfit to rule, you are not worthless. All things have worth. You are a sister and a role model. You aren't going to die anytime soon, so make the best of your worth."

"I... What is it that you want?"

"To help," he simply stated. "Such emotions should not be bottled up, no matter how well you mask them. I assume your conscience is clearer than it has been in a long time. Such thoughts are unbecoming of a princess. Also, it's almost morning."

"It's almost morning?!"

"You simply lost track of time. Show your worth, Princess Luna."

Princess Luna huffed. "Despite the method of your assistance, I do feel like the cloud inside my head has become more... clear than before."

Yatava nodded. "I see. Before you go, that wing and body of yours need fixing."

With a light tap of his stave, Yatava magically restores Princess Luna's body. It was a rush of relief filling her body, and Princess Luna felt better than she ever has.

"You still trot the road of darkness, little filly, but know this: The darkness is malleable and subject to change," he wisely said. "Stride down the road, and never stray. It's a hard one you chose, but it can change by your volition; remember that always."

Princess Luna nodded. Yatava tapped his wooden stave two times and teleported Princess Luna on the balcony in Canterlot Castle.

After collecting herself from the teleport, Princess Luna hurriedly strode down the hall to gather her overslept elder sister. Luckily, the Sun Goddess is already up and about, but something was odd about her that Princess Luna noticed. Princess Celestia had her sheets on her back, an unkempt mane, and faint drops of drool dripping and dribbling on her matted coat from her mouth as she waddles down the hall half-asleep. Princess Luna rolled her eyes and joined her sister.

Princess Celestia gave her younger sister a dull smile and a faint wave from his weakened hoof. "Good morning, Luna..."

Princess Luna began to lightly scowl at her sister. "Sister, you're late again."

"For what?" The Sun Goddess rubbed her head in confusion before letting out a loud, obnoxious yawn.

Princess Luna scoffed. "Oh, don't know... raising the sun perhaps?"

Princess Celestia chuckled and waved lazily towards her little sister. "Oh, that. Thanks for reminding me."

"'Oh, that'? Sister, please take this more seriously and go to bed at reasonable hours. You and I both have meetings later on today, there are celebrations taking place in the coming weeks, and you have tons of paperwork to do. Quit being lazy!"

Princess Celestia nuzzled her sister lovingly, however, Princess Luna didn't reciprocate the gesture, still eying the drops of drool with mild disgust. "I love you. I can always rely on you to keep me on track. You were always on top of things back then. Maybe I should let you raise the sun..."

The Azure Princess broke away from her sister's wet embrace. "You dare insinuate that I do your job can shrug off your duties, you lazy bum? Somepony needs to make sure you get up, you know. Hurry up and raise the sun!"

Princess Celestia playfully stood at attention and placed her hoof on her forehead like a royal guard. "Yes, ma'am. As I said many times before, you would be a great ruler."

Princess Celestia went to the balcony and started raising the sun with a dopey look on her face leaving Princess Luna alone in the hall. She held her chest and smiled, giggling a bit."

"I love you too. Now time for work!"

The day had just begun, and Princess Luna is pumped to give it her all.