(?) - Unkown years before Nightmare Moon.
Working long and hard into the day was very taxing on Princess Luna given her usual nocturnal nature. But she couldn't give up now, not after all the sleepless days she had spent perfecting her recipe. This, would change everything, most probably. Chocolate and milk, both delicious and oh so different from one another but she was dead set on meshing her favorite candy and dairy product together into some new perfection. The combination often reminded the Princess of the Night of her own relationship with her elder sister Celestia.
Two different entities co-existing in harmony for the betterment of all Pony kind.
Now if she could just get this chocolate milk to do the same, surely it would do double the good. After being booted from the castle kitchen and other locations several times over, she felt her room was now the only place she had left to carry out her work. Sure blending the ingredients together was simple enough but it had to be more than that. It had to be perfect. And she had no shortage of time needed to devote herself to this little project. In these peaceful times, the Kingdom of Equestria could practically run itself.
That simple fact troubled her sister to no end.
She would say, 'Don't be so carefree Luna. This could merely be the calm before a great and turbulent storm. We must remain vigilant.'
A knock came at the door. "Luna are you in there?" called out Celestia, barging in before Luna could respond.
Luna didn't bother to look up from studying her notes. "I believe you just answered your own question before I could, sister."
Celestia smiled sheepishly. "Sorry, I shall be more respectful next time." Her gaze panned over her siblings room, all seemed neat and in it's place save for that small patch of unholiness in the corner that was filled with a pile of milk bottles and chocolate bar wrappers.
Quietly, Celestia gobbled down the last third of an abandoned chocolate bar left lying on the floor. "You know Luna-"
"Yes, yes. I should be asleep and saving my energies for the imminent moment when the lives of all of Pony kind are threatened by some as-of-yet unforeseen foe!" Luna interjected. "I see you got your mane in a bit of a twist? Too bad, I've got to get this mix right. I have almost..." she trailed off, concentrating on mixing the confectionery concoction in front of her with a steadily increasing speed.
"Don't you think you've maybe spent a little too much time on this project of your's already? How many ways can there possibly be to mix chocolate with milk?"
Luna shot a semi-piercing gaze at Celestia, obviously offended. "Hmph...Is that a serious query, sister? I've got notes you know. Lot and lots and lots of notes, from my many moons of research! So given your love of note taking, surely that must amount for something in your eyes?" The night pony haphazardly guzzled down her latest creation at once, giving it no time to breathe.
Celestia nibbled on another bit of candy she'd found after committing the un-princess-like act of rummaging through her sister's trash. "Luna, you've only been at this for just two days. And I've told you before, the second batch you gave me to try was practically perfect. Why go on?"
" 'Practically perfect' will not suffice, Celestia." At once Luna used her powers to condense a mass of wrappers almost as large as her bed down to the size of a mere volleyball and tossed it into the waste basket. It blew apart upon making contact with the heavy wad. "And that second batch will be nothing but a distant memory once you treat your taste buds to my very latest creation!"
Celestia magically grasped the newest bottle that Luna had levitated over to her. "Okay, if it will help get your focus back on your royal duties, I will try it."
Luna watched anxiously as her sister slowly moved the top of the bottle to her muzzle, taking in the fragrance as both a joy and a precautionary measure. Then she drank it. A mere sip at first then, before she knew it the whole thing had been downed a fraction of a second later.
Luna's heart beat rapidly, that was the very reaction she had been hoping for. No words spoken, just a pony genuinely devouring and enjoying her product with gusto.
Celestia was ecstatic. "Woah, Luna..." Wide eyed she gazed at the bottle, "This was the most amazing drink I have ever tasted in all my life. Absolutely wonderful work!"
Nothing but silence came from Luna as there were no words to describe how happy she was right at that moment. Just a massive, head weight increasing smile was plastered on her face.
"Oh sister, this has made me most happy." Okay, maybe there were some words to describe her inner delight. "Why I haven't been filled with joy like this since we both got our cutie marks!"
A very pleased Celestia embraced her little sister. "I am happy you met with success, Luna. But what are you going to do now that you've done it?"
By now if the smile Luna bore grew any wider her head would explode. "I am going to personally deliver a shipment of my patented 'Moon Milk' to some random citizens of our land!"
She placed a crudely drawn map of Equestria down on the table and placed a blindfold over Celestia's eyes. "Now just place your hoof down on the map after I spin you around three...or ten times and wherever you point is the lucky settlement that is to be graced with my royal presence."
"But Luna..." Celestia stopped herself. She had hoped the response would be that her sister would now return her focus to her duties.
"Just let her get this out of her system." she thought. "She'll end up going no matter what I say." Without saying a single word more on the matter she allowed Luna to spin her around. Then after being sufficiently disoriented she planted her right hoof down firmly on the table with an audible thunk.
"So, hehe, where will you be headed?"
"Hmm..." Luna examined the map. "Okay, sooo where you just chose is the complete and utter middle of nowhere. Not what I had in mind. But it looks like the closest place to where you landed is a fledgling, little settlement called, Manehattan. I still say it should've been named Ponyville but I digress, it shall do just fine." Almost immediately Luna took flight to depart.
"Wait!" Celestia shouted, more than a bit shocked by her sibling's rashness. "You're leaving right now, as in right now?"
Luna raised an eyebrow, almost confused by this query. "But of course dear sister, why delay my journey?"
"But I...u-um." Cele stammered, at a loss for words. "Okaaaay, I guess now is as good as ever but what about packing the milk properly or getting some sleep first and while you're at it, why don't you just stay here and treat the castle guards to your drink?"
"One, no packing is necessary as I shall prepare the beverage fresh on site. And two...you are right. I am tired and will start fresh tomorrow, thank you."
Luna took a deep breath inward, taking on a more serious demeanor before switching into her royal canterlot voice.
"AND THIRD, LET IF BE KNOWN THAT PRINCESS LUNA DOES NOT SHOW FAVORITISM TOWARDS THE PONIES THAT ARE CLOSEST IN PROXIMITY TO HER RESIDENCE. I CARE FOR ALL OF MY SUBJECTS EQUALLY." Her booming voice echoed throughout the castle halls, shaking even it's sturdily constructed walls. "There, now the ponies of the land won't be filled with envy at the castle guards being the first ponies to enjoy chocolate milk."
Suddenly in the distance, the sound of a eight layer cake that had just been completed and taken all morning to produce could be heard toppling over along with the alarmed gasp of poor lil' Gwetta the royal baker.
Celestia remained calm by gently placing her hoof to her forehead and letting out a deep, calming breath.
Luna knew immediately what her sister would say next. "Yes, yes Cele. I am aware of what has just happened. I shall go and give my sincerest apologies to Gwetta and clean it all up...yet again."