When Twilight approached the edges of the city, she realized that it had been surrounded by a very thick, brown wall. They were crenelated by what Twilight could only describe as 'teeth' with very thin slits between them. These teeth curved upwards and over a large section of the wall they were at, granting the patrolling equines cover from light ranged weaponry. Even though the mare couldn't see it, she could hear the grinding of gears on and in the towers built within the perimeter. Whatever they were holding was heavy enough to require gears to move them. She assumed they were catapults and ballistae, but she didn't know what was used in Saddle Arabia. The gates leading into the desert were wide open, and four guards were stationed on both sides.
The guards were dressed in brown, rounded armor covered by white sheets of cloth supposedly meant to reflect the sunlight. Their armor looked like it was made from several stretched, oval-shaped slabs of the same brown metal and held in place by red strings, but seeing as they didn't budge even slightly when the guard approached Twilight, the strings appeared more decorative than anything.
"What are you doing here, pony?" the guard asked. "No pony can leave Tasaniyy without proper guidance and water supplies."
The mare cleared her throat. "I was told that somepony wanted to speak with me outside. There's a house or something out there away from the main path?"
The guard looked at Twilight then Spike, and his mouth took the shape of an 'o'. "You're the one I was told about. You must understand, the necromancers that live here tend to be...eccentric with their creations. I thought you were one of them. Very well. There's a wagon outside parked along the wall to the right."
Twilight paused, perplexed. "How do you know I'm not one of them?"
The guard leaned in, his voice quiet. "Because only those of us that work for their Highness the Lugalik know of that particular spot in the desert." He smiled as he stood back up. "Now get going," he said. "The desert gets worse at night. You shouldn't have trouble finding it."
What the guard had claimed was true: There was a wagon with three large barrels of wood waiting in the shade being guarded by two Saddle Arabians. They let her leave after seeing the undead dragon and confirming Twilight's identity. Spike grabbed the wagon and started pulling it as the two wandered reluctantly into the desert. The path mentioned was a long strip of near-white sand in the yellow sea of granules that the mare had to traverse. Looking behind her, Twilight could see the city shrinking away little by little and started having second thoughts. She didn't like the idea of traveling this vast wasteland on her own, but it was similar to the frozen landscapes that made up the territory of the Crystal Empire.
Plus, she was so close to her goal. This time it was the guards themselves that approached Twilight and her contact was supposedly linked to whatever it was that lived in the palace at the capital. To her surprise, while the desert was essentially empty, the dunes did not rise very high, leaving her able to see some semblance of a town or village in the great distances beyond, but their images were blurry. The mirage of something nearby reflecting off the sand. A few desert animals skittered about from the mare's approach, like serpents, furry mammals Twilight couldn't identify, and some arachnids. With the heat and the sand came strong gusts of wind that pushed the desert away from some large, very smooth outcrops of stone that had been polished by the winds and the grains that buffeted them for centuries. Twilight was amazed by the idea and hoped she could replicate it for Princess Celestia when she came back. A nice statue made from this stone would be perfect. Plus, they wouldn't just be pure white like all the others had a tendency to be, and no pony seemed capable of painting those they got their hooves on.
As time passed by, Twilight continued to drink from her barrels and felt a slight relief from the gusts of wind hitting her and the sun's gradual descent. Did the council's mages lower the sun here too? It was the other side of the world. They couldn't have just been left like this when Celestia was around. It was something else, wasn't it? As she mulled over the concept, Spike punted away a black scorpion that was about to sting her and drew her attention to something in the far distance just barely hidden by a dune. Moving slightly, Twilight made out exactly what the rhyming equine had told her: A small house sitting just outside what she believed to be a pretty big oasis. It could have been a small lake if the amount of foliage and trees were anything to go by. A veritable ring of emeralds in an ocean of gold.
"That way, Spike!" Twilight declared.
The trip took several more hours, and by the time Twilight had managed to get with a few dozen feet of the simple house, night time had already started to fall and the night was beginning to break through. The mare was engrossed with the art of the sky: Seas of white dots resting on semi-transparent beds of color as white streaks soared across them to vanish into the void. Large, twinkling spots of yellow, orange, and red making themselves known among their peers and demanding attention be focused solely on them. It was quite a sight that the mare never got to see when the mountains exhaled their mists into the skies constantly, blocking everything outside of moonlight.
Cold winds started blowing across the black sands, digging deep into Twilight's body. Shivering and unwilling to deal with this problem further, she went to the house and knocked on the wooden door. It was made with old, eaten-through lumber that left a bunch of holes and gaps, but it was still easy to accidentally push open.
"Hello?" Twilight called out. "Anypony here? I was told you knew the whereabouts of Princess Celestia?"
While the house wasn't much to look at from the outside, it was even less to look at from the inside. The exterior had been made with clay or mud likely assembled using the nearby oasis and had no fancy details to it like those in Tasaniyy. It was just a cube, and the interior was barren. A pile of straw as a bed and some wrapped with a few strings to act as a pillow. A few dented pots and pans resting on a primitive oven and stove with an opening charred black by fire, and a single window to the left of the entrance. Even Twilight couldn't live like this.
"Does a hermit live here?" she asked aloud.
"I am here," a voice seemingly called from afar. "Approach the stove."
Twilight hesitated. "Is this some kind of trap?" the mare asked.
"You want answers, don't you?"
The mare gulped nervously and steeled herself. "Alright, Spike. Let's do this," she said with a trembling voice.
The moment she did as she was told, Twilight and Spike were warped somewhere unknown. However, the mare recognized the dampness and odor of stagnant air anywhere: She was in a cave system. A cave system that replicated the night sky almost perfectly. The ground had been polished smooth and acted as a small 'plate' of pristine water that reflected the night sky floating above. Something had caught in the corner of the mare's eye, revealing that source of the glint was several astrolabes and telescopes of varying sizes and shapes placed to the left of where Twilight had arrived and were sitting there, shining with the oil used to polish their frames. Several more were sitting in pieces strewn about the cave floor but placed meticulously for reassembly and easy recovery. To the right, Twilight spotted several significantly better items of furniture compared to what was above: A proper bed with a large, comfy mattress covered in thick, blue comforters replete with a few pillows of varying sizes and colors. There was a metal stove sitting against the wall that whomever lived here used for cooking their meals and heating water. There were three tables of different sizes and heights placed meticulously around the area as well. A short one sat alone, surrounded by thick cloth for somepony to sit at. Another, slightly higher one, was several feet away and was accompanied by large couches. A few books were strewn about haphazardly on the table. A third was sitting on its own against the wall next to the bed and held a halfway-melted candle on its dark surface as well as an old quill and several inkwells in tiny shelves built into the table itself.
"What is all this?" Twilight wondered aloud.
"It's my work," a voice said.
Twilight spun around, unable to see the source and beginning to stress. "Please, don't tease me," Twilight begged.
"Fine, fine. I never get many visitors outside of a few of the same Saddle Arabians that work at the palace." The voice snickered. "They love their astronomy."
A shape fell through the night sky above and landed in the water, deforming the carefully tendered reflection. The pony that showed herself was almost completely night-blue. Her mane and tail resembled a flowing nebula with white edges and reddened tips, and her cutie mark depicted a glowing crescent moon in parting clouds. Better yet, she was an alicorn.
"Wh-wh-wh-p-p-p-Princess Luna?!" Twilight stammered. "Y-you're my contact?"
The mare nodded, her cyan eyes glowing faintly in the darkness of the cave. "Yes." She unfurled her wings. "This is where I've been hiding this whole time," she said. "After I was cleansed of the Nightmare by the Elements of Harmony, I was not privy to my sister's presence. Even when I returned I could not find her." She grit her teeth. "And then I learned that my sister was executed like a common criminal by the rabble of Equestria. The Element of Magic, whatever her name was, told me the 'council' expected the elements to eliminate me and that I should flee, so I came to Saddle Arabia in exile after..." She paused, her eyes growing wide. "After much searching." The alicorn walked over to Twilight and looked up at Spike who continued to stare at its master. "And I see that my sister's former apprentice really did become a necromancer." Luna looked back at Twilight and hummed. "And what will you do after you've accomplished your task? Dig ever deeper into necromancy?"
Twilight shook her head. "Oh no, of course not! It's all to bring Princess Celestia back," she announced cheerfully. "Once she's back I'll stop it since there's nothing else for me to need to learn."
Luna's brows furrowed, curiosity and confusion filling her every fiber. "And your research?"
The unicorn coughed nervously and tapped the ground with a hoof. "W-well, I don't want it to be lost. I hate knowledge disappearing. I'll keep it stored somewhere. Hidden. Safe!"
"I see...And your purpose afterward? Since you were my sister's prized subject, I imagine that you would want to go back to learning in her school."
Twilight chuckled nervously and waved a hoof at the alicorn. "I'm too old for that now. No. I...I think that...maybe...I could be a doctor of some kind? I could specialize in...necrosis and other ailments that kill parts of the body."
Luna pursed her lips and looked around her home, trying to parse what Twilight had told her. "And so you are here to learn of the whereabouts of my sister."
She was taken aback by her guest's eager nodding. "Of course!" the unicorn declared.
"Well, being sisters, and alicorns at that, we have a certain...connection, especially with what we were meant to do with sun and moon." She cleared her throat and flew over to the depiction of the night sky and started redefining the colors somehow. "So you were right to come to me and I was right to tell them to send you to me," the alicorn stated.
"Then...where is she?" Twilight asked.
"You won't like the answer."