The sun is due to rise in 10 minutes. Out of habit, Celestia stirs herself awake beneath her bedsheets. She was greeted by the usual darkness in her room, though for some reason, it seemed much darker. Seeing nothing but the colour black, Celestia's first instinct was that Discord had rendered her blind. She flailed her front hooves out from under the sheets and tried to stare at them. Her frantic blinking made the faint noise of her eyelashes scratching up against fabric. Lifting her hoof up to her face, she could feel the incriminating item. She lifted it up and became fraught with confusion. "A blindfold?" She immediately gasped at the sound of her voice, which was not her own.
Upon another realization, Celestia flings the sheets clear off the end of the bed. She thinks nothing of the pink robe she was wearing and lifts it up to reveal her flank. What she saw was not her sun, but a few blue jewels. With another gasp, she shifts her head around to inspect her room: A sewing machine, mannequins, a wardrobe, shelves of fabric and string... and a full-body mirror. She scrambles over while removing the robe. Standing still and staring right into the face of one of her protege's closest friends had her jaw drop. Discord had put her in Rarity's body.
She soon growled and began to let out a cursing of a certain someone's name, but she was cut off by a shrill squeal coming from beyond her door. She gasped at the sudden sound, but quickly remembered that Rarity had a little sister. "Sweetie Belle?" Celestia asked herself, mostly guessing the sister's name. Celestia walked out of her room and down the hall to where she heard the scream. Before knocking, she heard some panicked breathing.
"No, no! This isn't happening! How could this have befallen us?!" The filly's voice bellowed from within the room on the other side. Celestia began to wonder what could have Sweetie Belle all worked up, but then considered how a filly of her age would use a word such as 'befallen'. Sweetie Belle continued, "I cannot believe this! I must be in one of this filly's dreams."
That last phrase immediately supported Celestia's suspicion. She knocks on Sweetie's door nervously, begging to come inside. "Sister! Let me in!"
Sweetie Belle gasped and tried to not to get the older sibling worried. "Nothing is the matter!" She hollered back. "Return to what you were doing previously!"
Bingo! That was Luna, without a doubt. Celestia promptly tried barging in by twisting the handle of the door. The twitching and resistance quickly alerted her that it was locked. In a haste, she then tried to teleport into the room. With a flash of light and a "poof", Celestia infiltrated her way into Sweetie's room. While the spell was successful, the host-mare's lack in proficiency with advanced magic struck Celestia with a sharp but quickly faded migraine.
The filly reared back from the white mare's sudden entrance and tried to play it cool. "Good morning, sister!" She greeted with an appalling facade. "I am quite surprised the princesses have not started the day off proper yet." She pointed to the window.
"That's because both the princesses are right here!" Celestia stated with great force.
"What?"
"Luna! It's me! Celestia!"
"What?!" Luna exclaimed from within the child's body. "Celestia? How could this happen?! Why are we in the bodies of Twilight's friends?"
Celestia faced away from her sister and donned a flat and stern face. "I know exactly how..." She growled out from between her teeth.
"DIS--"
"--COOOOOOOORRRRD!!!" Celestia's booming voice echoed inside her royal chambers. A once regal figure now poised like a rabid manticore. She growled and ignited her horn in a large fiery yellow aura.
Just behind her, Discord phases into the room through her door in a neat suit and carrying a large serving dish. "You called for service?" The dastardly serpent replied.
The being he will know as Rarity until further notice wasted no time in turning around and pouncing him to the ground. She snarled at him inches away from his face.
Discord kept a slight look of confusion on his face rather than fear. After a few seconds of being blown on by the alicorn's nostrils, he spoke up nonchalantly. "What seems to be the problem?" Rarity backed up and back-hoofed him on the side of face, causing his entire mug to spin around the rest of head rapidly before slowing down and settling back in its regular position. "I can see you're upset." He noted.
Rarity forced a smile and walked away from him. She breathed deeply before answering him. "Upset? Oh no. Why would I be? I just woke up on this saturday morning to find that I'm in the body of our beloved sun princess. I have no idea how to do her job, and I cannot do mine. The latter of which involves spending every waking moment of this weekend filling an order for a high-end client. I'm not upset!" She scoffs in a mocking fashion and turns back to face Discord. "I'm A B S O L U T E L Y L I V I D . . ."
Discord stands up and brushes himself off. He walks toward her without a hint of caution. "Now, now. There's no reason to blow your top." He rests his arm around Rarity's shoulder, much to her chagrin. "After all, this is what she wanted."
Rarity's expression went completely dead as she sluggishly angled her head to stare directly back at Discord with the blankest look in her eyes. "She... explicitly asked for me to become princess for a day?"
Several seconds went by. Discord could finally recognize and register the insurmountable disdain the mare is bottling up. One wrong word could send him off the deep end. He twiddles his thumbs. "Well... No, but--"
A small platoon of solar guards were sitting calmly at their table in the luncheon area. Ambient chatter in all directions. The entire room went silent once they heard a resounding thud that was much akin to an explosion from the floor above them. They could even feel the entire castle shake.
Soon enough, a crudely ovular shape cracked into the ceiling. As debris finished falling into some of the guards' breakfasts, the whole abrasion fell in a single piece and landed in the middle of the table. The guards within collateral distance tensed up and stared in shock at the smoke-black splotch that covered the top. That splotch soon opened its eyes and lifted a paper-thin arm and positioned it above the eyes.
Discord peeled his flattened and sooty face off the chunk of royal bed chamber floor and stuck his thumb in his mouth to reinflate it. He and the guards looked up through the hole to see Celestia leaning over and looking down to them. She yelled out, "...without my notice!?!"
The guard to Discord's right sincerely inquired on the conundrum. "What have you done this time?"
Discord turned to him. "Nothing world-ending, I assure you." He took his finger and ran it through the remaining contents of the guard's bowl. He sampled the food he scraped up. "Who puts salt and pepper in their oatmeal?"
Eager to return to business, Discord snapped his fingers to return the piece of building he laid upon back in its place, leaving a whole room of worried and confused guards who will not get an answer as to why their boss is so angry. Another snap and he stood upright and clean. With a vivid look of concern -more for his own safety-, Discord clasps his claws together. "I suppose I do owe you an explanation."
"That would be a start." Rarity exhales out.
A distraught Celestia lays on the fashionista's bed. She would be focusing on how she'd get back at Discord, but she quickly became preoccupied by thoughts of how Equestria could run without her or Luna technically in power. Fearing for her kingdom, she set her eyes on the window and bore witness to the still-night sky. She wished her magical prowess came with her just so she could cycle to day. But if there was anything that teleporting taught her, it was that Rarity's body couldn't handle the strain of any higher forms of magic.
Luna fared no better. She angrily stomped around the room and growled. "What did I ever do to deserve this? That comment about your flank was nothing more than pushing your buttons!"
"I assure you none of this is your fault, Luna." Celestia got off the bed and walked over to comfort her sister. "When I made that deal with Discord, I wasn't expecting anything like this. And I certainly did not want you to get involved."
"Oh?" Luna inquired, "so if whatever he had up his sleeves actually did turn out to be fun, you would not have wanted to share?"
"What? No! Ugh... You know what I mean." Celestia walked back to bed. "But it's nice to know you still have a sense of humour." She smiled.
"It won't last long," said Luna. "The second I lay eyes on Discord, I'm not going to hesitate in--" She is cut off by a bright flash of light on the side of the room.
Discord has appeared inside with what looked like Celestia.
"YOU!!" Luna kept true to her promise and immediately went to jump him. She latched onto his torso and began beating down on his chest with an adorably powerless pounding.
Discord gave her little attention as he soon turned to Celestia laying on the bed. "Have you two gotten settled in?"
Seeing the clown of a god and herself from the outside left her with only one important question. "If I'm not mistaken, that should be you in there, isn't it, Rarity?"
Rarity looked down at herself with a quelled assumption and sighs. "Yes, Princess Celestia, it's me." She then grabs Luna off of Discord and sets her down. "I just hope you're okay, Sweetie Belle."
Luna calms down after her assault and bore a look that said "yeah, about that..."
Rarity quickly became worried. "What is it?" She turns back to Celestia who had a similar expression.
"I'm afraid that's Luna."
"What?!" Rarity walked back up to Discord to stare him down once again. "Why did you have to bring our sister's into this?!"
"I didn't have to," he confessed. "But the temptation was too strong to overcome."
Rarity's eyes went wide. "Oh no..."
Sweetie Belle leapt off the lunar princess' balcony with her new wings spread out. "I can flyyyy!!" She exclaimed in total excitement. Her extacy was cut short as she soon found herself plummeting toward the ground below, screaming the whole way. She belly-flops on the grass, leaving an imprint in the process.