This is written from King Whirlwind's point of view.

I looked down at the view below. Beautiful. Valleys, forests, rivers and waterfalls. It was pure paradise. This has always been my favourite place.
From this point I could see the border that crossed to Equestria, and behind me was the rest of the kingdom my wife and I ruled together. The Jewel Empire.
Suddenly I heard wing beats and my eldest foal, Prince Storm Cloud, landed beside me, his red and yellow mane blowing in the wind. He was in full armour, gleaming in the sun handsomely.
“Hello Father.” He said.
“How is camp coming along?” I asked.
“Really good!” He replied. “This is going to be the most successful training camp, I assure you. I’m so honoured that you let me be in full charge this time.” He added with a grin.
“One day you will be king, my son. You need to learn.” I replied, giving him a warm smile.
“No, I think Sparkle deserves it far more than me. She’s way more intelligent, pretty and she’s already adored by the entire kingdom.” He said, looking out at the view too.
“If you wish. It’s obviously your choice. I do not want to pressure you.” I sighed. “Controlling a kingdom, even with your mother, is very hard. As well as keeping in mind that she bears the Kingdom’s Jewel. But someday you’ll find a mare and be happy.” Storm Cloud didn’t reply. He looked lost in thought.
All of a sudden we heard more beating wings. I looked around in surprise to see two blue armoured Pegasi flying quickly towards us. We both backed up to let them land. They both bowed down, before getting up to speak.
“Your Highness, an urgent message you need to hear. We need you down in the camp now.” Said one of them.
“From who?” I asked.
“A castle guard… too much to explain. You need to come.” Said the other seriously. Storm and I looked at each other, before following the soldiers as they jumped from the cliff and swooped sharply downwards.
We alighted on the ground and galloped over to where a huddled group of soldiers were. They removed their helmets and stepped back as we approached.
Upon the ground lay a unicorn. His deep green tail was singed and his armour dented. He opened his eyes and looked at me, before getting to his feet. He tried to do it quick, but he looked like he was in terrible pain.
He bowed before me but I beckoned him up. “Rise. I hear you have a message.”
“Indeed, your highness.” He said with a groan. “It’s about your daughter, Wildfire."
“My sister?” wondered Storm Cloud. “Why, what has she done?”
“She’s… she’s gone insane. The entire empire is threatened if nopony stops her…” There were many gasps from around the area, but I help up my hoof to silence them.
“Why are you in such a terrible state? What on earth has happened?” I asked in shock. The unicorn gave me a longing look.
“She’s transformed… it’s so much like that Equestrian tale…” he said.
“The Mare in the Moon?” interrupted Storm.
“Yes! She’s turned wicked! But it’s far worse, she’s locked up all the other royals and turned all the knights and guards into fire monsters.” He moaned. “I was lucky to escape. I’ve been teleporting everywhere, trying to find you, King Whirlwind. She’s been in power for nearly a whole week.”
More gasped and yells.
I sat down on my haunches. This was awful. My own daughter, threatening the kingdom. I looked around to see everypony else whispering to one another, some looking anxiously over at me.
I stood and spread my wings, signalling for them all to silence and look over. I beckoned for them to come closer.
“So sorry, your highness,” said a dark grey earth pony. “But shouldn’t we go straight to the palace at once?” I shook my head patiently.
“No. We need to carefully plan this. She sounds powerful.” I said. That received some strange looks, but most of them nodded.
“Where should we start, your highness?”
* * *
The wind whipped quickly through my mane as I flew through the air. I beat my wings as hard as I could, soaring over the kingdom. Surrounding me were my soldiers, all the Pegasus ones. The unicorns had teleported themselves and the earth ponies just ahead, and were going to keep teleporting from place to place as we went over.
In the distance I could see the majestic white palace, its torrents towering above the forest and towns. My stomach had a horrible, nervous feeling in the pit of it; I was so worried for my family. Including Wildfire. What kind of magic had overpowered her? If it was magic…
Beneath me I saw a colourful patchwork of ponies, before they all started disappearing in puffs of flame. We would nearly be there.
I beat my wings harder, making it tougher for the other Pegasi to keep up. Storm came up beside me, squinting at the castle that we were fast approaching.
Within moments I knew this was where we needed to be. Beneath I sighted the ground dwelling soldiers, and I lit up my horn to signal for the others to follow me down. I swooped towards the ground, not flapping my wings, then I went up, landing smoothly upon the grass in the clearing.
The others all thudded down beside me, and Storm was checking to see everypony was OK. We were going to divide ourselves. I was going to signal the Fireballs from the palace, so they would attack.
I closed my eyes and focused. As my horn began to light up, I threw my head back. A huge lightning bolt of bright yellow magic exploded from it, creating a hole in the clouds. They began to darken and swirl, going around and around. The wind picked up, and I shut my eyes as tight as I could.
I created a swirling storm above. These don’t happen normally, only with powerful magic, which was bound to make the guards in the castle curious. When the storm was fully going, I released, panting. I opened my eyes and looked closely at the storm. We needed to move. I yelled out and half of my army followed, as we galloped away into the forest. Storm stayed with the others, ready to fight the on-coming army. I glanced at the castle, suddenly spotting little tiny bits of fire coming from it. Fireballs. The plan was coming along.
I galloped forward through the trees, closely followed by the army. We had to keep low, hidden in the thick bushland, so they didn’t go for us instead of the others. I watched as they quickly began shooting towards Storm and the soldiers. They didn’t notice us.
It was time to storm the castle. My castle.
* * *
We reached the edge of the forest and came to some meadows. They were small, and led straight into the capital, Laheb City. It would probably be safe, these were just the outskirts, but we probably had to travel over.
“Teleport to the gates!” I ordered the Unicorns and Earth ponies. They respectively saluted me and each unicorn touched a hornless pony, and they suddenly all vanished. I nodded behind me and lifted myself off the ground, soaring into the sky. The others followed and we swooped silently over the buildings.
Laheb City was the most gorgeous, fashionable and sophisticated city in all of the Jewel Empire. The buildings were tall and elegant, and the rich pony nobles had gorgeous houses with marble torrents. The streets were neat cobblestone, and all around were lovely trees that draped over the houses and streets.
Town square was even more attractive, with an enormous statue fountain of an alicorn soldier holding the flag of the Jewel Empire. Obviously, Alicorns were only part of royalty, but it was to represent us.
As we went over the square, ponies started looking up and pointing. Some began to cheer, probably celebrating our return. I had no clue as to whether or not they knew about Wildfire, but they probably did.
Up ahead, in the centre of the city, was the palace. It was lovely, made almost entirely of marble, with gold plated towers and a huge flag of the Empire on the top of the highest one.
I swooped down and landed on the cobblestones right in front of the enormous silver gates, the top bar glittering with tiny sapphires and rubies. I wondered what lay inside the palace. There was only one way to find out.
I flapped my wings and flew over the gate. The others followed and we went over the gardens. We arrived at the drawbridge that went over a moat. Most of the palace didn’t have the fancy gates and the drawbridges, only this main entrance into the castle at the front. The city surrounded the palace, but this was the only place you could enter without teleporting.
The drawbridge was down, but on each side of the entrance were guards. Fireball guards.
Just then something clicked. The soldiers who came to give us the message mentioned that Wildfire changed them into fireballs. Maybe there was a way to reverse it? Maybe I didn’t to distract those other ones. I just hoped my son and the soldiers figured it out.
As I began to walk towards the entrance, the two fireballs used their magic to create a fiery force field across the door.
“Hal,” one of them started, trying to halt me, but I pointed my horn at him and shot a burst of magic out. It hit the Fireball straight in the chest, going through his armour and into his heart. He choked for a moment, before an electric string of magic went up his body, transforming him back into a regular unicorn.
“Wha…. What happened?” he mumbling, rubbing his head with his hoof.
“Crescent!” a voice suddenly cried from behind me. A guard ran out to greet his friend.
“Marine Flame?” mumbled the ex-fireball.
I let them be, before blasting the second guard. He turned into a normal pony too, and a few others went up to greet him.
This was going to be easy.
I marched forward through the doors, the others following. The two unicorns who had been changed back came too, getting a full explanation of what was happening from their peers.
We went down the magnificent entrance hall, being careful not to come across anypony we didn’t need to.
I suddenly decided to let the others try and handle Wildfire. There were so many, they didn’t need me.
“Crystal Shield! Get here for a moment!” I called out to one of the higher knights. A Pegasus made his way around the others, saluting before me.
“I need you to help the others get to my daughter. I’m going to the dungeons to look for my wife.” I ended the sentence looking behind me.
“Yes, sir.” Said Shield. He gave me a brief bow before returning to the others. I imagined the dark dungeons in my mind, closing my eyes, before I suddenly felt like I was getting sucked into a cold tube, the air left my lungs, when I abruptly I was thrown onto the ground.
I rubbed my head and looked around. I was in the dungeons. I turned around, my hooves echoing on the stone. I began walking down the corridor, into the darkness. Somepony had taken away the torches, and I made a little light with my horn.
All of a sudden I heard clopping hoof-steps behind me, and saw a Fireball walking down behind me. I blasted my spell into his heart before he could see me, and he collapsed to the ground as a white Pegasus stallion.
I began to charge down the hall, the cells on either side. I saw they housed innocent ponies, like the servants and random nobles. But they had to wait, as much as it hurt.
“Father! Father!” I heard the choked cries of one of my daughters down the hall.
“Fire Fighter!” I cried. I galloped down the hall, to find a dark cell. Inside was my daughter, princess Fire Fighter.
“Oh my stars are you OK?” I asked, sticking my muzzle through the bars. She looked at me through sad eyes. Her helmet, armour and shoes were off, and her mane that was usually tied up and stuck out of her helmet hung in a sad knot around her shoulders. Her eyes were glazed over and she looked ill.
“Please, get me out…” she moaned, her voice cracking. I felt tears in my eyes.
“Oh, what happened? How could your sister do this to you? Wildfire…” I said. At the mention of her name Fighter stomped her hoof and pinned her ears.
“I hate her.” She muttered. “I HATE HER! SHE’S NOT MY SISTER!!” she screamed and reared up, causing me to back away.
“I’ll get you out! Wait, I know what to do!” he said. “I put a spell on this dungeon to step ponies teleporting out….” I closed my eyes and focused my mind. Slowly I felt my heart being crushed by the weight of the spell, and I struggled to stand. Suddenly a sheet of magic spread out from my horn, surrounding the cells. I went up to the ceiling and disappeared. I’d done it.
I heard cries and whinnies from around me, and all of a sudden bursts of light erupted from each and every cell, with ponies disappearing, taking each other away.
“I can’t… I’m too weak…” whispered Fire Fighter.
Suddenly I reached out with my hoof and touched her. She looked up, and I teleported her out of the cell right next to me. “We need to find your mother.” I said.
“We can’t, I heard they’re got her someplace you’ll never find, they wanted to make extra precautions.” She muttered.
At her words my heart cracked. Poor Aka. But one day, I was going to find her. Right now, I needed to get my daughter safe, and maybe even Sparkle Flame too. We were all going to overcome this threat, one hoof at a time.