"Off with her head."
The clang of armour echoed through the hall as every Royal Guard scrambled to carry out the order. Successive blasts of purple magic took down the first three; another's chestplate was pierced by a sharp horn, but the unicorn's head was then parted from her body following a well-timed slice from behind. Dangling from the mane, it was brought before the princess, whose starry tail swished with glee.
"Most excellent. Now, reinstate Thursday moon celebrations. Mandate store openings from eleven till five. Sentence to death any pony with a tan, and bring the jester. She amuses me."
With each command, a Royal Guard jumped to action as fast as their heavy armour would allow, until the princess was alone with the head of Twilight Sparkle. And five more Guards posted outside the room.
"I know what you're up to," she spat. Twilight did not reply. "You shall never be a princess, and you shall never take my throne. I have worked tirelessly through night and day to get where I am today—and to get this kingdom where it is today—so I will not have it ruined by some insolent, nosey know-it-all such as y—" She was interrupted as a cross-eyed pegasus dressed in a pointy hat and back-to-front curtain flittered in, looking everywhere but at the princess.
"So you arrive. Entertain me."
Starting at the boom of the princess's voice, the jester crashed through a stained glass window depicting an angelic Celestia raising the sun before a crowd of rejoicing ponies. Moonlight flooded the room, and the princess cackled.
Spooked further, the jester darted about the room with erratic flaps of the wings, all while waving her hoofs about in an effort to gallop away, but meeting only air and several chandeliers, which fell to the floor with great crashes echoing throughout the vast hall, each one spooking the pegasus more.
A twinkle came from one of the more intact shards of glass. It wasn't from the moon. The princess's laugh faded, and she glanced out the now-missing window, eyes narrowing. A glistening white pony slowly flapping her wings rose, framed by the gently rising sun. Her horn shone as a midsummer day.
"Sister." She spoke slowly. "Dawn has come." She descended upon the throne, hoofs firmly meeting the ground with a clop. Her wings remained outstretched. "Guards," she called, shouting now. "Send my sister to the dungeons. The sun is my domain." The Royal Guards filed back in, bowing hurriedly to the Celestia before a beam of magic forced them to scatter.
Celestia watched proudly as her subjects advanced on her sister, clumsily dodging arcane blasts and attempting to tackle her to the ground before she rose above them with a single flap of her wings. They threw their ceremonial spears, and the shaft of one hit Luna's wing, sending her to the ground and into the waiting hoofs of the Royal Guard. As she was dragged away writhing and screaming, the princess saw the head of her student.
"How could she do this to you?" She spoke softly, cradling Twilight's still-warm head in tender hoofs. Raising her voice to an order, she boomed, "Initiate fourteen days national mourning. Black must be worn, all entertainment—theatres, sports, the like—is to be closed. Only necessary shops may open—providing only between nine and ten, with dimmed lights and playing suitably sad music. Anypony found to smile, unless sadly in fond remembrance of my student, shall join my sister. So will any who converse with the moon." Her speech was broken by the jester absently flying into her field of view. "Now is no time for jesters. I'd have her head off but for the entrance she gave me. Guards, fetch the royal seamstress." As the pattering of hoofs running off to fulfill her orders died out, Luna's screams could again be heard.
"Your Royal Highness, Princess Celestia, The Righteous The Most Honourable Master of The Glorious Kingdom of Equestria, the dawn-bringer, darkness-quencher—"
"Yes, yes. Get on with it."
"The seamstress comes."
As promised, she trotted in, treading lightly but not slowly. She wore an almost elegant black gown, and gave a slight curtsey as she approached.
"I have a task for you. Sew the head back on my student. Begin at once."
She replied in a voice like velvet: "Of course, my princess." The echo had yet to settle and the seamstress had already pulled a thread from an impossibly-small handbag concealed in the folds of her dress.
The princess turned away and addressed the Guard. "My faithful student shall be made a princess. Her coronation must be today. Commission a window commemorating the event to replace the one broken. Fourteen days of national celebration shall begin at once. Organise luncheons, parties, parades." One stallion scribbled down the princess's orders. "Oh, and invite Cadance."
He looked up from his paper. "Of course, ma'am, your majesty, princess, only—" he began.
"Spit it out. No time for dilly-dally."
"We're currently at war with the Crystal Empire."
"Hmmph. I don't remember starting that one. Or was it because of the farmland?"
"You didn't start it. It was your sister."
"Then make peace. Any other wars I should know about?"
"Well, there's Yakyakistan—"
"Good." The princess turned back to face the seamstress. "How's Twilight coming along?"
"I'm here. I think." She replied, getting used to having a voice again. Celestia examined closely her neck, feeling for where the blade had landed.
"Brilliant work." She gave a slight nod towards the seamstress, who trotted out, the slightest hint of satisfaction on her face. Softer now, the princess added, "Everything's okay now, Twi. We're making you an alicorn. Imagine that, big, purple wings to prance about with!"
"Oh, that's," she tried to reply. "Thank you. When's the coronation?"
"Started three minutes ago."
The room rapidly dimmed. A shadowy figure smashed through the newly-installed window of a rather sleepy Twilight being crowned. The moon shone between the navy feathers of her outstretched wings.
"Sister," she bellowed. "The moon is my domain." She descended before the ongoing coronation. "Off with her head."
Author's Note
Been sitting on this one for quite a while now (as you can probably tell)