Disclaimer: I do not own anything that is MLP. I am simply a fan telling a story.
The sun was falling low in the sky when Princess Luna emerged from her room. The guards posted outside her door bowed low as she passed, and the dark blue mare nodded her head in greeting. It had been several years since she had escaped from the moon. Several years since Twilight Sparkle and her friends had freed her from the jealousy and greed that had become her master. Several years since she had shed the name Nightmare Moon and become Luna once more. And still, Luna felt that many of the ponies in Canterlot – many of the ponies in all of Equestria – still saw her as the power hungry monster that she had once been.
Slowly, the princess of the night made her way to the watch tower where Celestia was sure to be, unless she had other duties to perform that evening. It was the place where every night, Luna took her position and raised the moon, so all the ponies across their great land could sleep in peace, knowing there was light to guard them, and somepony watching over them, as they slept.
"Good evening, sister," Celestia greeted warmly as Luna joined her side. Both mares watched as the sun slowly sank below the mountains to the west. "Or should I say good morning?"
Luna smiled quietly at her elder sister, but the truth of her words stung. One of the burdens of being the guardian of the night required the alicorn to catch up on sleep during the hours of daylight. She often missed out on much of the day to day lives of her subjects, and that fact alone caused her much heartache. But as a princess, she had duties she must perform. She wouldn't let Celestia, or the citizens of Equestria down ever again.
"Good evening," Luna responded, her horn lighting up as she effortlessly lifted the moon into the sky. "I hope all is well."
"Yes, indeed," Celestia murmured, touching her horn to Luna's shoulder for a moment. The younger alicorn leaned into her older sister, relishing in the rare contact. "Peace is wonderful to see in action. Not a sign of trouble across the entire kingdom. All is well indeed."
"That is good to hear." Luna nodded a goodbye to Celestia as the older princess made her way back to the center of the castle. No doubt to her own bedroom. Even the lead ruler of Equestria needed her sleep.
Turning her attention to the mountains in the west, Luna began her vigil. Her eyes remaining wide open, scanning the skies and ground for any signs of trouble, despite the weariness she felt. For the past moon or so, Luna had been sleeping rather fitfully. When she was first returned to her body, her nightmares had been plagued with images of Nightmare Moon, of herself. Plunging the world into darkness, and attacking her only sister. Celestia comforted her many days, assuring the young alicorn that the horrid visions would go away.
With time, they did. No longer were Luna's days haunted with the images of a past she longed to forget. Now, her dreams were filled with a past she was just beginning to remember. A time before her thoughts of hatred and jealously emerged. It was if every time she slept, she relived moments of her past – her childhood. The friends she made, the memories of life before becoming a princess. All were gone now. Not a single pony, apart from Celestia, still remained from her time as a filly. How could they? She and Celestia were the only two immortal ponies in all of Equestria. Nopony could ever hope to live as long as she. But that fact didn't prevent Luna from remembering.
Luna's earliest memory was of Celestia, curled up at her side, singing her to sleep. They were deep underground, in some sort of cave, with torches all around giving off a warm orange glow. The infant Luna was crying. She knew it was time for everypony to sleep, and though she could not see the sky, she also knew the moon was currently rising over the hilltops.
She could never explain how she knew what the outside world looked like. Her entire childhood took place in a series of underground caverns. The world above was chaotic, according to her parents. Discord ruled all of Equestria. Chocolate milk fell from pink, cotton candy clouds. Fish swam through the air. Trees floated upside-down in the air. And while the young filly didn't know what chocolate milk or cotton candy was, she didn't think it sounded all that bad.
The young Luna didn't want to sleep. The moon was rising, and she was awake. She wanted to venture outside, to the world above them.
It was important for them to stay hidden, Celestia always said, echoing their parents, whenever Luna asked why they could never see 'outside'. If they ventured outside now, Discord would find them, and then there would be no hope for the ponies of Equestria.
"We are destined to save them, Luna," Celestia would tell her every night as she rocked the young filly to sleep. "But not just yet. We have to grow up big and strong first, and for that you need sleep."
Luna and Celestia were different from the other ponies. There were many ponies hiding below ground from Discord. Ponies of many different talents. There were earth ponies, and unicorns, and pegasi families from all across Equestria that had made their way here once Discord had assumed the throne. But none were quite like the two sisters. They were alicorns.
And not just any type of alicorn. A special pony, who proved themselves to be kind and compassionate, loyal and wise, brave and just, had the ability within them to become an alicorn, if they chose goodness and showed themselves to be a leader in the face of adversity. Luna and Celestia were an even rarer breed. These sisters were born alicorns. The only two in the entire history of Equestria.
Their mother had known they were destined for greatness the moment Celestia had been born. She and their father had fled their home and retreated underground with the day old alicorn the moment they could. Hope had finally entered the world, and they would do whatever it took to keep that hope alive.
Then Luna was born, and that spark of hope turned into a bright, burning flame. Two alicorns, born of the same bloodline. Their power would be unmatched, so long as they grew up with goodness in their hearts, and the knowledge that someday, they would be benevolent rulers of Equestria.
Moons came and went, and Luna found it as difficult as ever to sleep when everyone else laid down their heads. She learned to subdue her energy and redirect it to more productive tasks. As soon as she was old enough, Luna took a position with the night watchponies, as a junior assistant. Her parents were hesitant at first. They didn't like the idea of her being so far away – so close to the surface. But Luna was insistent, and the other ponies promised she would be safe.
It was there, during the night watch, that Luna made her first friend. She was standing alert, mirroring the rigid stance of the other watchponies, her eyes fixed on the ground below. They were up on a cliff embedded in the wall of a large cavern. It was the only place that Luna had seen so far where the moonlight filtered in through the rooftop. Blue Armor, the self-appointed captain of their watch team, said the hole had been covered up with various shrubs and rocks found on the mountainside, but a little space had been left so the ponies underneath could see at night.
Luna's job, along with the other watchponies, was to look out for anypony up after curfew. They had certain rules in effect for reason, to protect the ponies that sought refuge from the chaotic world above. No one was to be out of bed after the moon rose a quarter way into the sky. The watchponies made sure to enforce that rule, and to keep a close eye on the entrance way, in case it was discovered by someone on the outside.
One particular night, Luna was at her post, scanning the cavern floor for anypony breaking curfew when she spotted a tiny light emerging from one of the passageways. She glanced over at Blue Armor, who had spotted the light as well. It was traveling closer, followed by the clip-clopping of a pair of hooves.
"Who is that," one of the watchponies whispered as the guilty pony came into view. "I can't tell."
"Garnet, is that your son?"
Luna turned her head and saw the broad unicorn nod his head slowly, "I'll go speak with him." Garnet made a move to jump down from the ledge, but Blue Armor stuck a hoof out to prevent him.
"Go ahead," he murmured to Luna, whose eyes widened in surprise. They were trusting her with her very own mission? "You're ready. Just remember what we told you."
The young alicorn nodded vigorously and scurried to the edge of the ledge. The young unicorn colt was still there, a soft blue glow radiating from his horn. Luna crouched. She could feel some of the adults shift instinctively toward her, but the young filly was already high in the air.
Granted, the ledge wasn't terribly high off the ground. Luna most likely could have jumped off and landed on the ground, only slightly hurting her legs. But Luna was an alicorn. And though she had never used them until that night, Luna had wings. Instinctively, she spread them wide, blocking out a section of the moonlight. The young unicorn looked up in shock as her shadow passed over him. He squeaked in alarm and backed up a few steps as the dark coated filly glided through the air and landed without a sound by his side.
"What are you doing out here?" the alicorn hissed, an attempt to keep her voice down. "Don't you know it's past curfew?"
"Don't you know it's past curfew?" the unicorn shot back, without missing a beat. Luna stared into his light green eyes for a moment, puzzled by his reaction. She hadn't met many ponies her age living in the caverns, and those that she did meet seemed to be quite frightened of her.
"Of course I know," she retorted, giving a slight huff. "I'm part of the night-watch. And you're not. I'm rep-ri-man-ding you." Luna beamed, happy to have used the new word Celestia had taught her earlier that week as they watched a young Pegasus being scolded by her mother for flying too high.
"You can't do that!" the colt argued, angry that she was seemingly smarter than him. "You're just a filly, barely older than I am."
"So?" the filly shot back, then caught herself. She would not stoop to his level. What would Celestia say at a time like this? "The moon has already traveled halfway across the sky," she pointed out, her voice lowering significantly. "We don't want Discord to find us, so we have to be quiet and stay out of sight."
The young unicorn glanced over at the adults, silently watching the pair. "Ok," he said finally, turning his bright eyes back to Luna. "I'm sorry."
Luna smiled at him, and the colt smiled back. "You should come visit sometime," he said, flicking his grey ears forward. "I live down that way." The alicorn's eyes traveled down the path from which he had come.
"Ok," she agreed. Other than her parents and Celestia, Luna hadn't had much interaction with anypony that lived down in the caves. "I'll come find you when I wake up in the morning."
The young unicorn beamed, and Luna felt a strange feeling stirring in her heart. "Look daddy!" he whispered excitedly, bouncing over to the older unicorn, who had returned to the ground floor. "I made a new friend."
"That you did, my son. That you did."
Princess Luna blinked her eyes, and slowly her mind returned to the present. It hadn't appeared that much time had passes, but Luna knew. She had always known what time it was, thanks to her strong connection with the moon. She had been lost in her memories for a little less than an hour, but it was an hour she should have been watching over her kingdom. The alicorn princess knew better than to let her thoughts control her in such a way. She swore to herself, it wouldn't happen again.
Or, at least she hoped not.