Twilight's Castle was a curious structure, capturing Human Twilight's eyes as she wandered, clopping around on her new hooves. "Fascinating," was her favorite word of the day, gaping at each thing she found to stare at. Her glasses were still on her face, though she had to adjust them a few times, as they had transformed with her.
She paused at a window, gazing out into the night, the moonlight shimmering over the castle walls. "Is that the moon?" It was a silvery disc, just like the one she left, but it was also alien and different. "I'm on another world, or reality, or, hm."
The pony Twilight caught up with her doppelganger. "I'm glad you're enjoying yourself."
"Why are you larger?" Human Twilight whirled on her larger, alicorn, copy. "And you have wings. We are otherwise very similar in appearance." She touched her own neck, then the mane that adorned it. "I really have a mane. This is interesting. It's not fur, or hair. The structure is denser than I would have guessed." She pawed the ground with a hoof. "I do miss hands. I have notes to take."
Pony Twilight curled an arm around her guest's neck, guiding her along. "You can have your hands back once we get you through the portal.
Human Twilight resisted, or tried. The glow of her larger self's magic picked her up and drew her along. "Weren't you curious, when you came to our world?"
"Deeply, but I also was in the middle of a crisis, so, I admit, I didn't have too long to take notes." Pony Twilight descended the stairs towards the mirror that had started it all. "Now it's my job to keep things on the right side of the portal, for the health of both worlds." She gestured at the device that had a cloth draped over it, and removed that fabric with a snap of her magic.
The mirror shone in the torchlight, glistening like a rippling lake as they approached it.
Human Twilight reached out with a forehoof to touch it, but withdrew, head lowered, ears flattened. "It's not that I don't like my world, or have things to do there. There's just so much to see here though."
Pony Twilight touched her nose to her copy. "I can understand that feeling. Tell you what; I'll inform Sunset Shimmer and she'll put you in contact with me, so I can answer your burning pony questions."
Human Twilight gasped with glee. "You'd really do that?"
"Yes. I have my duties to Equestria, but I have access to many books. I'm sure I could get you the knowledge you seek, if it's within my power." Twilight began an arcane series of motions to make her promise serious. "Now, if you would?" She inclined her head at the portal. "You have school."
"And you have a princess to be." Human Twilight began to hop into the mirror, hopping backwards, but stopped at the last moment to give the princess a hug with a soft neigh. "I'll miss you, sister."
Twilight hugged the younger her tightly. "And I'll miss you too. Goodbye."
With a bright sparkling flash, Human Twilight was sent to her own world and Pony Twilight turned the whole thing off, so no new lost humans would wander through. "Now, Crescent? Are you still here?" She was taken aback by how quiet it was as she entered the lobby, leaving behind the basement for the greater chamber beyond.
Crescent sat there, draped in a blanket and munching on some cereal, ears back and head low.
Twilight sat beside the tiny little moon filly. "There you are." She watched the cereal chewing a moment. "That was quite some adventure you just had."
"I am hungry." Crescent raised the bowl to her lips, trying to drink what remained of the milk inside.
"Makes sense." Twilight helped herself to a box of her own. "But I don't think that's why you're upset. Would you like to share with me?"
Crescent huffed as she lowered the bowl, grabbing for another box, this one something sweet and chocolatey. "I met a new friend today, a nice girl named Diamond. She knows I'm not human, but she isn't afraid of me."
Twilight flinched. "Ah. And you miss her?"
"She wanted to see this world." Crescent folded her arms. "And I wanted to show it to her, but I'm here now, and she isn't." She laid her head on Twilight's side. "And I'll probably never see her again, will I?"
"Never say never." Twilight reached over and picked up the small child, draping her across her lap, keeping her close and cozy as she stroked Crescent's mane. "Though the odds aren't great." She let out a little sigh. "Sunset mentioned you went there for me. May I know what you were planning?"
"I was going to check on Sunset, but the thought occurred to me that I might have someone else that needs checking on as well." Crescent patted her own chest gently with a hoof as she spoke, snuggling against Twilight's side with a content hum in her throat. "Sunset didn't need me. She had things under control." She flipped an ear to the side. "Why were you worried about her?"
Twilight jumped in a nervous laugh. "Crescent, I am a nervous pony. I get worried about a lot of things, given the chance." She smooched the top of Crescent's head. "I was worried about you. I'm glad you're back."
Crescent snuggled into Twilight, clinging tightly, embracing the alicorn with all four of her limbs as she hugged the grown mare as close as she could. "Me too." She sniffed gently, burying her head against Twilight's soft chest and tickling mane. "But now I'm home." She shifted so her chin rested on Twilight's chest and they could gaze into each other's eyes. "Don't tell mom what I was up to."
Twilight inclined her head at that. "Won't you do that?"
Crescent froze a moment before it hit her. "Oh. Yes. Yes, I will." She rubbed behind her head. "This is a new sensation, having something I don't want to share with her. Is that normal?"
Twilight snorted with amusement, grinning from ear to ear as she cuddled the little filly with great care. "I'm afraid so. Most ponies don't share everything with any other pony, even their mom. Can you pick what you share or not? I don't think Luna will be upset if you keep a little secret or two."
Crescent flipped one ear forward and back. "How much is a little?" She grabbed a nearby notepad and wrote the question down. "How much is a little?"
"Like, not something bad, but maybe you did something that didn't go according to plan?" Twilight chuckled gently. "This little adventure didn't hurt anything, just surprised some ponies. So, you have my permission to keep this memory to yourself, if you like. It'll be our secret."
Crescent whirled on Twilight with wide eyes. "Really?" Her horn began to glow with a gentle hue. "That's allowed? You're sure?"
"Yes." Twilight squeezed the little filly that was at once ancient and also a little child. "Did you enjoy yourself?"
"I did." Crescent hopped from Twilight's lap to scurry in circles about the room. "It was fun!" She tripped on her blanket and crashed to the floor, laughing uproariously at the absurdity of it all. "That world is very different from ours." She sat up, little wings flapping. "But I like this one better. Oh!" She looked outside. "I should head home, mom will be worried." She groaned gently. "Not too much though, I hope. I don't want to frighten her."
"I doubt you'll worry her that much, but you should be off before she comes to bed." Twilight got up herself and gestured towards the front door. "I'll see you next time, when I'm awake." She rolled her eyes gently. "No sneaking into the portal again."
Crescent got a mischievous glint in her eye. "Are you sure? I wouldn't mind having a few friends visit, or making a few friends of my own there. It was pretty nice. No one is afraid of me, not even Diamond."
Twilight gently nudged Crescent towards the door. "Absolutely not. Now, if you want to visit pony Diamond, she may prove to be a fast friend as well."
Crescent blinked, as if amazed at the idea. "There's a pony Diamond?!" She hopped about with excitement. "Does she have a cutie mark like Diamond does?"
"Yes, a tiara. She is Diamond Tiara, just the one that's always been a pony, instead of a human." She got Crescent out the door. "Just remember, she hasn't met you yet. Just because you said hello to her human copy doesn't get you to skip that, okay?"
Crescent clasped her front hooves together with a joyous neigh. "I have a new friend!" She leaned against Twilight's side, rubbing against the princess as if she were a feline seeking affection. "Thank you, Twilight." With all that settled, she raced away in a streak, launching herself into the sky to return to Canterlot with a delighted squeal of an adventure completed.
Luna staggered towards bed, yawning with the coming morning. She glanced around, feeling like she was forgetting something, but unable to quite remember what it was. The sense of a piece of her heart missing lingered as she rolled into bed, plopping onto the sheets with a tired sigh, gazing at the empty spot beside her, where Crescent should have been, and yet, the space was not occupied by her beloved daughter, which stung in ways she couldn't describe as she buried her face under her pillow.
Quiet settled on the room. She lost track of how much time had passed, but something thumped down on top of her. She got out a muffled complaint into the covering pillow. "It is too early for your nonsense, daughter."
Crescent licked her face. "Gooood morning, mom! I'm back!"
Luna ripped the pillow from her face and tossed it away, wrapping Crescent in a warm embrace. It all rushed back, what she had forgotten. "Where have you been hiding?"
"Let me share." With a slow breath, Crescent shared her day and evening with her mother, keeping bits of it to herself that time. "Twilight was a very nice host."
"She is a darling." Luna yawned with fatigue. "But your mother is tired." She rolled over, carrying Crescent with her to cuddle the little dream-filly as she sank back into sleep.
Crescent wasn't done though. She snuggled close and whispered into her mother's ear. "The human world isn't bad at all. Everyone there is so nice."
Luna hummed with approval, only to pause. Human world? But she was too tired to pry into what shenanigans her dream creation had reached. She was soon quite asleep, snoozing peacefully with Crescent to hold.
Crescent nestled in against her mother, nuzzling the warm fur of the mare that protected her with soft caresses of her muzzle as she savored the closeness of their bond, letting out a little sigh of her own, releasing a tiny breath of magic that caused Luna's mane to flutter gently before settling back down upon her sleeping form.