One Flap of a Butterfly's Wing

Prolouge - A Bitter Pill to Swallow

"Achoo!"

A frilly, white handkerchief soon found itself levitating in front of the monarch's reddened muzzle, appearing with what could only be described as robotic precision. "Are you sure you're alright, Princess?"

Princess Celestia stared at the finely-woven cloth before her with burdened eyes, debating with herself over whether or not she should even bother with the thing. On one hoof, she had always found handkerchiefs to be a bit on the grody side of things. On the other hoof, she would hate to ruin her freshly-washed coat so early in the day. She probably would have kept this mental back-and-forth going for a few more moments had it not been for the growing trail of mucus running down her upper lip.

"Yes, I assure you, I'm —sniff— fine." she replied, wiping the handkerchief across her face. "I've lived for over a thousand years. I think I can handle a cold."

With a sigh, the butler took back the cloth and folded it up. 'If you say so, your highness." he said, contradicting himself almost immediately by taking a few steps backward to distance himself from the Princess as she let out another round of raspy coughs. "Your health is my number-one priority. Please do not hesitate to let me know if there's anything you need."

"Thank y-" She began, her words coming out rough and congested. Celestia closed her eyes as she cleared her throat, cringing as the inflamed passageway protested the action. "Thank you. Your concern is much appreciated. Now please, I would appreciate some privacy."

The butler said nothing, nodding respectfully as he exited the bedroom.

The sound of Celestia's complaining went hand-in-hand with the sound of the door closing as the butler made his way out.

"Ugh..." she groaned, cupping her aching forehead between her hooves. "This can't be happening already!"

To an outside observer, her condition didn't make sense - she was an alicorn. She wasn't supposed to get sick. She was Princess Celestia, the millennia-old, divine ruler of one of the largest and most powerful realms in the known world. She was an alicorn, a prestigious race blessed with longevity, good health, and eternal youth.

Or, at least, that's what she told everypony.

It was true — being an alicorn definitely had its perks, but anypony with the smallest notion of common sense knew that nothing, not even a god, can last forever.

She was getting weaker. The eternal life wielded by alicorns might seem like a blessing to the uninitiated, but the truth was that it came at a steep cost. Sure, powerful magic can allow an organism to never age past a certain point, but magic is energy, and if Starswirl's third law is to be believed, energy degrades over time.

There was a reason why Celestia had begun taking students under her wing. Her magic was getting weaker, and Equestria would soon be left defenseless. Of course, Luna would still be there to take her place, but she would soon succumb to the same circumstances as well. So what was she to do? The answer was simple enough: Find another pony with just as much intelligence and virtuosity as she once did, and pass her remaining power down to her.

After thousands of years, the magic infused into her at her birth had at last run out, and she had become mortal. Her flowing, ethereal hair would soon begin to gray. Her smooth, flawless face would become rough and wrinkled. Then, like she had watched her thousands of years worth of peers do before her, she would perish.

But Princess Celestia did not fear death — she was much too wise to do something as silly as that. She feared for Equestria.

She had thought that Twilight's coronation would be the end of the dark cloud of anxiety and uncertainty that constantly loomed above her. She had thought that she had had it all figured out, and she could pass on in peace without having to worry about the future of the land she cared for so much. But now, after the unfortunate chain of events that lead to Twilight's abdication, she wasn't so sure anymore.