Luna's heart was pounding as she gingerly took another step up the mountain. With one misstep, the loose obsidian would slip free, and the princess and her two traveling companions would fall. Luna would not be completely doomed to die, because her still premature wings could hold her weight.
She could not say the same for her traveling companion, though, being an Earth pony and heavy-set. Luna's wings were not strong enough to catch him, and her magic was not developed enough to levitate him. The princess could surely not keep the farmer and herself from crashing on the black, sharp rock below.
It was sweltering on this volcano, just as it was back home. The azure alicorn almost felt like turning back, returning home alone, taking her citizens to another, less hot region. Yes! There they could set up another kingdom, and...
No. What a stupid idea. Nopony would make it. The heat was spread so far out; most of the population would perish from the heat before they even left Equestria.
But that's why Luna was up here. It was because of the ponies that were dying right now that the princess was traveling far up this mountain to find her older sister and stop the scorching sun storm that plagued the kingdom. The alicorn suddenly found her strength again, and started to run.
The farmer smiled. He'd seen the princess' discouragement on the way to this volcanic mountain. He'd wanted to say something, but he thought it's be best for her to find her own might within herself.
"Here." Luna stopped after a few more minutes of trekking at the base of a glowing palace of blazing red and orange hues. "Celestia's in there. I feel her presence." The alicorn put a hoof up to the Earth pony stallion. "Stay here, Macintosh. The flames of this castle would kill you the instant you touch them."
The farmer nodded, swiping a few drops of perspiration from his forehead with his burgundy hoof.
Luna, with a deep breath, entered the palace, both hopeful... and fearful.
***
"Celestia?" Luna called. She was aghast at how intricate the palace of molten lava was. It would be beautiful, if not for the intense heat emitted from the walls, floors, and, well, everything.
After a few more moments of searching, the young alicorn saw a bit of white for a second amid the warmer colors, before it disappeared again.
"Celestia!" Luna called loudly. Surprisingly, a reply came this time around.
"Leave this place, Luna! Immediately!"
The blue princess frowned and pursued whom she was certain was her older sibling.
When Celestia jumped to a blazing staircase, Luna followed. The ivory princess tried to coax her younger sibling.
"Luna, please, go back home! It's not safe for you on this mountain; you'll burn up within a few hours!"
"No!" The azure alicorn retorted. "You don't have to protect me, Celestia! I'm not afraid of the heat!" Both sisters continued to run up the long set of fiery steps. Luna continued to call out. "Please, don't push me out again! Please don't close the door! You don't need to keep away anymore..." Tears welled up in the young princess' eyes as she continued.
"Because, Tia."
The white alicorn stopped, shaking her head. Don't look back, just... just don't look back. But she went against her own will and turned her head toward her youngest sibling, looking sad, and a bit confused.
Luna smiled sadly. "For the first time in forever, you don't need to act aloof! Celestia, sister, we can fix this." She grabbed her sister's hoof with her own. "Hoof in hoof."
"Luna--"
The young princess interrupted. "We can climb down this mountain together, Tia. Nopony needs to live in fear! For the first time since I can remember, I will be right by your side here."
The sisters finally arrived in a large room of flaming wall, with a balcony overlooking the land. Celestia's heart had started to open up, but she refused. She didn't belong back in Equestria.
And Luna didn't belong here. She set her hoof on her sister's shoulder. "Lulu. Pleas return home. Your kingdom awaits! Go, be the queen you've always wanted to be! Open up the iron gates!"
"Celestia, but--"
"I know! You mean well, but leave me here! I may be alone, but I'm alone and free!" Celestia led her sister to the balcony, overlooking the sun that was just over the horizon. "Just... keep away, and you and Equestria will be kept safe from me!"
"Well..." Luna shifted nervously.
Tia tilted her head. "What?"
The blue alicorn sighed. "Actually we're not."
"What do you mean you're not?"
"I have a feeling you don't know."
"What do I not know?!" The older princess' hooves were mounted on her sister. Celestia quickly realized this and let go.
"Um..." Luna had tears in her eyes. "Equestria's burning up..."
Celestia was shocked. Burning up? Did that mean... ponies were... "No..."
Luna shook her head. "When you left, you accidentally created a storm of scorching fire above the kingdom. Our citizens are dying." But the young pony then had hope in her voice. "But it's alright! Now you can quench the flames!"
"N-no I can't! I... I don't know how!" Celestia's emotions of fear were becoming stronger, and little bursts of flame started to appear around her body, flying about the room.
Luna looked determined. "I know you can! You don't have to be afraid anymore..."
Celestia heard no more. She was in her own world, frantically running about the place, anxious and worried. "Oh, I'm such a fool! I'll never be free!" She tossed her head left and right. "There's no escape from this fire inside of me!"
"We can work this out together!" Luna's cries came from outside the growing swirl of flaming tongues around Celestia.
"I can't control this curse!"
"We can reverse this storm..."
Celestia started to weep. The mix of emotion was terrifying, and the fiery funnel surrounding her only grew stronger. "Luna, please, you'll only make it worse! There's so much pain! I'm so afraid!"
"We can face this trial together!" Luna persisted.
"No..." the fire princess let out a long cry.
"We can change this fate together!"
"I..."
"We will set everything free--"
"I CAAAN'T!!" Celestia absorbed all of the fire around her and suddenly released the energy, piercing through Luna's heart. The azure princess fell to the ground. Her cries for her elder sister stopped.
Everything stopped.
Celestia dropped to the ground where her younger sister had fallen, sliding a hoof under the blue princess' head, lifting it. "L... Luna?"
I couldn't control it. I'll never be able to control it. I'm destined to kill everyone... Including the only person I've truly loved since my parents died... Unstoppable tears fell from the ivory alicorn's eyes. And she never even got the chance to know I loved her! I never even got the chance to find that I loved her, until now. My sister... "Forgive me! Please!" Celestia embraced her young sibling. "If I could I would die instead of you! I just wish..."
Suddenly, magic energy began to flow out of the ivory alicorn and into her sister. "W-What?" A portion of the exuded energy formed into a form of a pony.
"You finally understand, Celestia. This curse can only be broken by true love. And not the true love of a significant other," the figure gestured to the blue pony on the floor. "But the love for family."
Celestia nodded. "So, Luna will come back?"
"Yes, but you, I'm afraid, will not. This energy is your life source, and without it, you will disappear into the whispers of the wind."
Celestia smiled. "That's alright. As long as my little sister is alive and well. I don't mind a bit of sacrifice." The princess laughed a bit as she saw her hoof slowly disappear. As she faded away, so did the flames of the palace.
When Celestia was completely gone, so was the curse. The volcano returned to the form of a typical mountain, and Luna was lowered to where Macintosh, the farmer still stood. The stallion was astonished. After a few seconds, Luna opened her eyes.
"M-Macintosh?" Luna arose and embraced the red Earth pony. But then she looked about her. "W... Where's Celestia?"
But a wind blew past the two on the mount, and through a whisper, Luna understood everything. "So... She did love me. After all this time of doubt. She really truly loved me."
Macintosh shook his head. "I'm sorry, but I still don't get it." Luna wrapped her hooves around him once again.
"That's alright. I'll explain it to you on the way back to Equestria."
From then on, Luna vowed to use the love her sister had had for her to rule her subjects kindly. And occasionally, she would look up at the stars and see a special constellation of a smiliing white alicorn.