“What do you see?” asked Luna from her position on the stairs.
“It is very deep, your Majesty” replied the thestral, hovering in the air by her side, “And I see nothing but these stairs spiralling downwards until they disappear. No traps so far as I can see.”
“Very well. We shall descend on the wing.”
At that, Luna alighted from the stairs and beat her wings in a slow backwinging motion, descending in the darkness alongside her thestral companion.
The winding stairs seemed to go on forever, each twist and turn adding to the rising tension that something horrible would happen and they would not be able to get out, but they both kept their worries to themselves.
“Your Majesty, I think I see something down there” said the thestral, “It looks like we are nearing the bottom.”
“Can you make out anything further?” Luna asked.
“I see a solitary entity with a warm body signature.”
“Very well” Luna deliberated, halting her descent and going into a hover, “I shall hail them. Be prepared to seek cover on the stairs or fly upwards like your life depends on it should that be Nightmare Moon down there.”
“Yes, your Majesty, I understand” came the business like reply.
“Hello!” boomed the Royal Canterlot Voice, “We are Princess Luna. Identify yourself please!”
She mentally facehoofed that after all these years, in times of stress she still referred to herself in first person plural, as had been accepted grammar in the olde Canterlot tongue.
“Luna!” a strangely distorted echo responded, “It’s me, Twilight! Am I glad to see you!”
“The pony identifying herself as Princess Twilight has started to fly towards us” the thestral remarked unemotionally.
“I think we can safely say that is her” said Luna cracking a smile, “Thank you.”
“My pleasure is to serve, your Majesty” he replied.
“Luna! Luna!” Twilight’s voice sounded less echoey the closer she came to her rescuers, until finally level with them, she reached out and gave Luna a very happy and tearful hug.
“Come, we may rejoice further once we are away from this accursed place” Luna warned, “It would be inadvisable to tarry longer than necessary lest we become sealed in.”
Luna led the way with more urgency than the caution she had exercised when entering the stairwell, the others keeping pace with her until they could see the glow of a moonlit night, beckoning them to the hole in the floor that would be their exit.
Although Luna had slowed her ascent as she neared the top, she still emerged unexpectedly quickly to the surprise of her sister and niece who were waiting for them, and had to ensure she stopped before bumping into the roof.
Celestia and Cadance watched expectantly as the next to emerge was Twilight, and when they saw her, they couldn’t help but cheer and clap their hooves happily, even though Royalty was supposed to show reserve at times of personal delight. This was different; Twilight was back!
Finally, the sharp eyed thestral appeared and positioned himself at a discrete distance away from the celebrating Princesses, but Luna turned her head towards him and motioned him to join the happy little crowd. Even he, a rigidly disciplined guard couldn’t help but crack a smile in the atmosphere of infectious happiness.
Later on, once the entrance to the secret stairwell had been sealed over again and the guard returned to his unit with a hastily hoofwritten note of commendation, the four most senior Princesses in Equestria sat down together in an antechamber attached to Cadance’s suite where they swapped stories and indulged in tea and cake.
Cadance held her forehooves up to cover her mouth, eyes wide in astonishment, as Twilight recounted her clash with Nightmare Moon through to its dramatic finale. Meanwhile, the two sisters exchanged glances, both wrestling with similar concerns.
With her tale told, Cadance clapped her hooves together excitedly and then rubbed away the tears that had run down her muzzle, before sitting back and exhaling a gasp of relief that it had all ended so well. Or had it. Twilight noticed the sisters looked a little distracted, and that bothered her.
“Celestia, Luna” she asked, “You’ve got something on your minds; what is it?”
The older sister gave a polite little cough to clear her throat as discretely as she could before replying, “Firstly, I am delighted to have you back safe and sound …”
“That’s hardly what’s bothering you is it Celestia?” Twilight observed.
“No, no it isn’t. I have only cast that spell once” she replied, giving a regretful glance to her sister, who returned the merest nod of forgiveness, “And even then, I needed the Elements of Harmony. How did you manage to do it all by yourself?”
“Well, to be honest I didn’t do it on my own” Twilight explained, “Nightmare Moon was channelling the power from Sombra’s dark crystals, and when our horns locked I could see that her worst fear was to be returned to the moon. When I cast a simple spell to blast her away, it seemed to get amplified, and before I knew it, she was on her way to the moon.”
“You mean, you used Sombra’s dark power against her?” Luna gasped.
“Maybe” Twilight answered with a shrug, "But it was more likely the Magic of Friendship I had summoned that gave so much power to the spell; I think the dark magic just improved the aim."
A concerned silence descended while the three other Princesses exchanged glances, each harbouring similar concerns that Equestria's monarch could have become tainted by casting such a powerful spell using, at least in part, Sombra's dark crystal magic.
“Is it possible” Cadance probed warily, “That you may have established some kind of permanent link with King Sombra or his magic?”
“I don’t think so” replied Twilight, “If I had, I wouldn’t have been trapped in the magic stairwell. No, I’m pretty sure it was the Magic of Friendship that made my spell so effective.”
Nods all round confirmed this as a reasonable deduction, although she would now never be totally free of concerns linking her to the dark crystal magic and Sombra himself.
It was Celestia who broke the brooding silence and changed the subject:
“We have also to consider what to do with Nightmare Moon now she is on display for all to see. Firstly, I am concerned for any ill effects this may have for my dear sister, and secondly, there is always the possibility that her continued presence on the moon may form the focus of a cult set upon freeing her.”
“From my perspective Tia, I shall suffer no worries or concerns about her being imprisoned on the moon, but I do appreciate the ethical dilemma posed by holding an enemy of the State on public display without trial, as it were. There may be long term implications if this is not handled appropriately.”
“I see both of those points” Twilight interrupted, helping herself to another slice of cake and casually sitting back down again, “But I think before we act in haste, we should take stock. You see, I couldn't help noticing that her image on the moon is a lot lighter compared with when Luna had been banished up there; didn't you see it too? Go take a look for yourselves.”
Intrigued, all three Princesses approached the nearest window with a clear view of the moon, and sure enough, the silhouette was weaker than it had been decades before.
Twilight did not need to see for herself; the looks on their faces told her she was right.
“You see, the Nightmare Moon I banished was not a real pony; Princess Luna owns the only body that she could have laid claim to, and so she is only an ethereal entity who happened to be able to manipulate Sombra’s dark crystal magic to create a body for herself. Now she’s separated from the crystals that gave her that power, her energy will fade.”
“Do you mean she will soon just fade away and be gone forever?” asked Cadance in surprise.
“I think the image of her head will disappear quite quickly" said Twilight, “But, in as far as Luna is immortal, we must assume that Nightmare Moon is too. If her reappearance this time has taught is anything, it’s that she is determined and we must never let our guard down. In practice, I should be most surprised it we don’t see her again in our lifetimes.”
“But we’re immortal, Twilight” Cadance noted.
“Right” agreed Twilight, calmly taking a sip of tea, “She’ll be back, I’m sure of that. Either the stars will align to help her or ponies may fly to the moon someday. One way or another, it will happen, but probably not for some time. More tea anypony?”