Twilight lay sphinxlike on the balcony outside Luna’s quarters, a scattering of hoof-thick musty tomes sprawled before her. At the unicorn’s side Luna sat on her haunches, starting into a moonless and cloudless sky.
“Another one, shall we, Twilight?” said Luna, though her gaze never left the midnight sky. “Celestia, though her efforts be praised, had little diligence in maintaining the stars during my exile. Many thanks to you, Twilight, for assisting me in restoring my heavens to their pristine state.”
“You’re welcome! Okay, give me a second,” Twilight muttered, one ear twitching as she squinted to read a page of cramped hoofwritten notes by starlight alone. Her ears perked as she tapped the page. “How about Epsilon Scorpii? It’s supposed to be a class K1 III red star, at least according to the original text, but it’s been blue since I’ve been stargazing.”
Luna smiled and lifted an eyebrow toward the little mare. “You mean, since you were born? I always assumed you had been a devoted stargazer from the moment you first drew breath.” Her horn flared dimly and briefly as a tiny speck near the horizon shifted almost imperceptibly from faded blue to barely pinkish. “Done! How have we fared?”
“That’s a dozen more we’ve corrected,” Twilight managed before stifling a yawn, “and I’m about done for the night.” Closing the book in her hooves, she returned the smile. “And I plead guilty, too. You’re right, I was fascinated by astronomy and the stars in general as far back as I can remember.”
Pausing for a long moment, the alicorn sighed deeply. “Your recall of ancient astronomy is gratifying, Twilight. Do you remember your ancient mythology as well? The tales of gods and goddesses?”
The smaller pony’s brow furrowed and she cocked her head as she looked up at the Moon Princess. “A little, I think. Probably not as much as I should, I suppose. I was always more interested in magic and the heavens than in old myths, really.”
“Ironic, in truth, for you yourself played a part in one of the grandest events of modern mythology,” she said. “Shall I tell you of your part in history, Little Spark?”
“Me? I don’t remember – “
Turning to face Twilight directly, Luna crouched and spoke in hushed tones. “Tell me, Twilight, of what sort were the old gods? What manner of beings were they said to be?”
Twilight’s heart pounded a little and she closed her eyes in concentration. “Well, there were … First, there were the primal forces which were conceived of as deities by the earliest ponies. Order and chaos, creation and destruction, that sort of thing.”
“Go on.”
“And then there were the more tangible forces, representing the physical world. Ponies worshiped goddesses and gods of storms, and the ocean, and the harvest – things they could touch and see.” Looking up, wide-eyed, she gasped, “And the moon!”
Grinning, Luna nodded. “Perceptive as usual, Twilight! Ponies did indeed worship the moon as a goddess, long millennia ago, and they worshiped me as its manifestation and its avatar. Yet I am here and there are no storm-gods walking Equestria, so something differed between those elder forces and myself.”
“You’re a pony,” Twilight blurted, over-loud, “like us. Okay, not like us entirely, but… I…” Her ears drooped low and she stared down at the mosaic floor. “I’m sorry, Luna, I didn’t mean it like that, I -”
Luna chuckled and lifted the librarian’s chin with a hoof. “You are not incorrect, love, and I am not offended. I am more like unto the ponies of Equestria than they realize. I sleep and eat and love and breathe and bleed just as they all do.” She leaned in close and whispered, “But then, what of Nightmare? She was made of shadow-stuff and dark dreams. What was she, this creature that possessed me?”
“She was,” Twilight started, then swallowed the words and retreated a bit. Her eyes darted back and forth as if scanning the text on some invisible page. Locking her eyes on Luna’s, she said, “A goddess?”
Luna wrinkled her muzzle and glanced away, a thick band of stars reflecting in her eyes. “Yes, Twilight. Nightmare was one of the old deities. Ponies knew her, feared her, and cursed her every time they woke.” She snapped her head back to face Twilight with a suddenness that sent the little mare recoiling and hissed, “And what becomes of these worldly gods when ponies lose their faith and explain away their powers? What happens when ponies forget their very existence?”
Twilight’s heart beat heavy in her throat at the sharpness of the question. She let second after echoing second tick by before whispering, “The old myths say that a goddess without worshipers will… will fade away. If they’re forgotten, they just…” She gulped and shrank backwards, “…die.”
Luna rose back onto her haunches and stared down at the trembling pony. “Twilight, what did the prophecies say about Nightmare Moon?”
Clearing her throat, Twilight lifted her head and spoke clearly, “That much I remember. The prophecies said, ‘the stars will aid in her escape’.” Silence filled the balcony before Twilight’s eyes grew wide and her pupils shrank. Shaking her head, she choked, “No! I…”
Luna sighed and nodded. “Yes, Twilight, you. Nightmare thought her vile actions a millennium ago would seal her place in Equestrian legend forever, but ponies have a remarkable capacity to suppress their worst memories. Nopony in all Equestria recognized Nightmare Moon upon her return. Nopony, that is, except you.”
Twilight stammered, “You mean… If I hadn’t recognized Nightmare Moon that day in Ponyville at the Summer Sun Celebration, if I hadn’t remembered her, then…?”
“Precisely. She would have faded from Equestria on her own, forgotten and all but powerless, regarded as little more than a showmare or conjurer of illusions. But because you recognized her, and because you spread word of her return to others, you gave her power enough to return not as a shadow of her former self, but in her full and terrible glory.” Laying a hoof on Twilight’s shaking shoulder, she said, “Yours, Twilight, were the stars that aided in Nightmare’s escape.”
“Luna!” Twilight rasped, shivering, “That… that’s not possible! That can’t be right! You mean, I - I was the one responsible for almost plunging Equestria in eternal night?”
Luna lay a great indigo wing across the quaking pony beside her. “And for saving it as well, love. You and your stars aided in my escape as well! And had Nightmare returned as but a shadow, and not at the height of her power, you would not have needed the Elements to defeat her. And had you not had cause to rediscover the Elements, we would thereby have been powerless against Discord.” Pulling her closer, she lay her head atop Twilight’s and said softly, “You are the mare of destiny and legend, Twilight. A pony of prophecy in your own right, moreso than you know.”