"You are sure you wish to do this?"
Princess Celestia looked down at the unicorn in front of her. She had dealt with this unicorn before, and only once could she have remembered it ever turning out badly. Even then, it hadn't really been her fault--Grand Galloping Galas never turned out well. It was a known issue that Celestia was still unsure how to fix.
"More than sure." The unicorn gazed back upwards with a determined, but serene, expression. "Remember, Princess, we are ever in your service--and by 'your' I naturally mean all of the Canterlot royal house. In fact, I consider it beyond an honor that you're even considering my offer."
Celestia and Rarity walked, the former leading the latter down the halls of Canterlot Castle. "Yes, well, when Twilight told me of your offer, I was most surprised, but also most intrigued." Their walk led up several steps, into Celestia's chambers, until reaching a sealed, intimidatingly large door at the back wall. A small application of magic from the princess, and it opened without so much as a creak.
The castle vault, perhaps? No, Rarity mused. Something far more personal. It had to be, since it was in far closer vicinity to the Princess's inner sanctum.
"And while I would normally question her for divulging enough castle secrets for you to make this offer at all..." She trotted inside, and thirty seconds later, came back with an object floating beside her. "...I suppose this case is the very definition of special."
Rarity looked at the object... a rock. She would have felt a sense of sardonic deja vu, but as she took hold of her own magic and rotated it in the air, she knew she agreed with Celestia's words.
"A keepsake from when my sister and I were..." Celestia hesitated. "...first separated. A shame it doesn't work for either of us, I suppose."
Rarity levitated the rock out of the window, observing the effects as it floated in the night sky. A short time later, she gave a satisfied nod.
"It only has to work for one. And I can make that happen. On that, Princess, you have my word."
At that moment that Rarity and Princess Celestia met eyes and exchanged smiles--one confident, the other trusting.
"Then take it," said Celestia, "with my blessing."
---
Two nights later, Princess Luna answered a knock at the her room's door, and saw the same unicorn which had been in Celestia's audience now staring up at her. "Rarity, is it?" Luna looked at the unicorn quizzically. "Of Ponyville, yes?"
Rarity nodded. "Yes. I trust your night has been well thus far?"
"Well... yes and no. Normally I would be out and about, especially on full moons such as this--I enjoy them so--but Sister insisted..." She stopped herself with a sigh. "No slight against you, of course. I already owe you and your friends so many unrepayable debts." Luna gestured with a single hoof for Rarity to walk in.
"Think naught of it." Rarity did so, levitating a clear plastic bag behind her in a rigid upright position. "And rest assured, I would not have asked for your time if I did not think what I had to offer would be worth it."
Rarity saw Luna's muzzle curl into the smallest of smiles, and she froze for a second, wondering if perhaps that last sentence had come off as boastful. If it had, there was no taking it back now. Confidence, Rarity. Confidence. It was the only way she'd be able to move up in society, in her business... anywhere. She decided to continue along her present path.
"Your offer, then," said Luna, in a bemused, almost singing, tone of voice. "Please, share it."
"Twilight Sparkle related to me your misgivings last Nightmare Night. Your insecurities, if you will."
Luna's muzzle now curled in the opposite direction as she rolled her eyes. "The ones that were on display, or the ones I confided in her once I was done being humiliated in front of the populace?"
Rarity nodded. "Yes."
Luna was silent for a few moments. "Fair. Pray, continue."
"By my calendar, and everypony else's in Equestria, this year's Nightmare Night is in exactly one week."
Luna stepped to her balcony and looked up at the full moon, a baleful look crossing her eyes. "I may or may not have been trying to forget that very fact. I admit nothing, however."
Rarity rested the bag on the bed. "Twilight and I figured--correctly, it seems--that perhaps old fears might have carried over. To that end, I thought that perhaps before this Nightmare Night, we could help put them to rest."
Luna looked at her bed. "And I suppose what is in that bag has something to do with it?"
Rarity willed the plastic away, revealing an elaborate piece of fabric. "That is our hope. But whether it does or not, it is yours to do with as you please, now and always."
Luna looked at the fabric on the bed, then back at Rarity, who was wearing an expectant grin, and sighed. "Rarity, I appreciate the thought. I truly do. Tales of your generosity have been told far and wide and I am flattered that I can finally witness it firsthoof. But any personal problems I may have with this year's holiday of the night? I can deal with them. Really."
Rarity shook her head. "Yes, yes, I am aware that you 'solved' your problem last year by allowing the myth of the monster you once were to become one of the star attractions." She met Luna's eyes. "But what of the mare, Princess?"
Luna's face instantly fell--subtly, but just enough for Rarity to notice when she'd found an opening. "How is it fair that the Princess herself not also get the attention she deserves, simply for being the Princess? I know you've you've mastered one side of yourself." Rarity levitated the fabric in front of Luna, the planet's gravity unfurling it to reveal a frilled black and navy dress in the princess's exact size.
"Allow me," said Rarity, "to help you master the other."
---
A changing screen materialized in front of Luna, who took the dress and stepped in from the right. Several seconds, ruffles and magic sparkles later, she emerged from the left in an outfit which, to both mares' surprise, left Luna gaping and near-breathless.
"Rarity, I must admit... this is beautiful." She ran a hoof over the fabric. "The texture, so soft, the frills, light in the breeze..." She closed her eyes and slowly twirled, a jubilant exhale escaping her lips. "In my youth, I would see Celestia wear elaborate pieces such as this." The small smile was back. "Only in far brighter colors."
"Your sister did collaborate with me during the design process. If I may..." Rarity placed a hoof on Luna's shoulder. "...she loves you more than words ever could say."
"Which is why she always appears afraid to say them." Luna sighed.
"Being able to read appearances is important," said Rarity. "It lets one know when one must take the initiative themselves." Silence ruled the room until Rarity decided to pull back this time. "Forgive me. I may have spoken out of turn."
"No, no," said Luna, shaking her head. "Not only are you generous... you are wise as well. Thank you, Rarity. I shall place this dress in a safe place until the appointed time-"
"Wait." Rarity held up a hoof. "There is one last thing."
Luna stopped. "Which is?"
Rarity's smile now matched Luna's of minutes past. "Will the moon."
"Will it?"
"Well, I'm not sure how you do it. But use your magic. Will it to move, to shine... anything."
"Oh. Um... well..." Luna looked the very definition of flustered. "...'tis an odd request, but..." Her horn glowed. The moon outside shone brighter than usual upon Equestria, to the point where the balcony might have had a chandelier directly atop it.
And then it happened. White stars and curved designs appeared everywhere along the navy lines of Luna's new dress. Again, Luna was speechless, which gave Rarity room to flourish.
"I call it Moonglow Fabric," the unicorn said. "For, uh obvious reasons. Ground up material from the very moon itself, salvaged from a different time, and woven into what you wear now. I do hope it is to your liking. As has been said before, we're glad you're back. The night just wasn't the same without you."
Silence ruled the room once again as Luna looked directly at Rarity, unblinking, but her eyes shaking just the same. Then, without warning, Rarity found herself levitated to face's level with the Princess of the Night. She was only able to let out a quick "Princess, I-" before being enveloped in twin, fabric-covered forelegs.
Finally came the whispers in her ear.
"Before tonight," uttered Luna, "I knew you were Equestria's grand heroines. As of this moment, however, I realize you have always been far more. You are gems, pure and genuine. Let none--not even any silly notions of 'modesty'--tell you otherwise. So your Princess demands." Luna firmed her hug, just in time for Rarity to return it.
"I will do my best," said Rarity, "so long as you tell your sister exactly what you just told me."
Luna chuckled. "Twilight always told me you were a shrewd businessmare. 'Tis a deal."