“Cadence!” Princess Twilight Sparkle broke into a rapid gallop and fairly flew across the Canterlot castle corridor to catch her former foalsitter and current fellow princess in an enthusiastic hug. “I didn't know you were going to be here too!”

“I've been here for a few days already, Twilight. Auntie Celestia said it was important, and had me take off for a whole month from the Crystal Empire.” Cadence returned the hug with added interest and a few bonus nuzzles. “I should have sent you a letter, but Shining Armor has been so busy shopping for the baby and Celestia had a special treat for me.” Cadence grinned. “She let me help raise the sun this morning.”

“No!” gasped Twilight Sparkle. “Princess Luna came to Ponyville last week and let me raise the moon with her too! The moon is all cool and calm, but there's a playful streak in her too. I think I might have made it laugh. Can the moon be ticklish? What did you think the sun was like?”

“The sun is a lot like Auntie Celestia, all warm and royal with a sense of majesty. It was really quite touching.” Cadence giggled. “I think it remembers you.”

“Oh.” Twilight blushed. “I really didn't get along with it very well when Tirek was rampaging around.”

“You did just fine,” said Cadence with a reassuring nod. “Did Aunt Celly tell you why she wanted to see us this evening?”

Twilight frowned with a slight narrowing of her brows. “Princess Celestia? Princess Luna told me to be here this evening, right before sunset.”

“That's odd.” Cadence's smile faded slightly and she looked back and forth down the empty corridor. “I know something is up, because for the last few days everypony has been giving me strange looks. I thought it was just because I was pregnant.”

“Hmm…” Twilight's frown grew deeper. “The same thing has been happening to me since I got to the castle. And I'm not pregnant.”

The two young alicorns walked side by side through the castle corridors and along hallways until they reached Celestia's huge bedroom suite. Two armored guards at the doorway, one in gold and the other in silver, opened the doors for them, and then closed them silently after they had entered.

At first, Twilight Sparkle thought the huge bedroom was unoccupied. Brilliant sunlight mixed into vibrant pastel hues filled the room, highlighting so many of the familiar collection of objects that Celestia had acquired over centuries of rule. Every one of them had a story associated with it, and even after spending over a decade as the Student of the Sun, Twilight still felt as if she had only scratched the surface of their history. As a young filly, she had exchanged stories with Cadence about Celestia's collection too, and had never heard a single duplicate tale about her life.

Since becoming an alicorn princess, Twilight had discovered that Princess Luna had a similar if somewhat smaller collection of memorable artifacts, ranging from tiny little blue sparkles nearly the size of a pinpoint, up to the stars in the sky which she knew individually by name and temperament. The Princess of the Moon had become a close friend to Twilight over the last year, and had even accidentally referred to her as 'sister' on occasion, which brought a delightful blush to Twilight Sparkle's cheeks whenever it happened. Luna was a much different princess than her sister, as different as the proverbial night and day, although they both had a sense of the theatre about them, a unique mixture of comedy, tragedy and drama.

Celestia's pale form and pastel mane was nearly invisible against the clouds spread out across the horizon, making a vibrant camouflage that was the only way to conceal an alicorn of her majestic size. The shadow that fell across the room from the balcony doorframe likewise concealed an alicorn, only one whose mane flowed with ethereal darkness. Luna's eyes were closed, as if in pain from the brilliant sunlight coursing in through the window, but both ears were unerringly pointed at Twilight and Cadence, and a look of divine patience and tranquility graced her delicate features as Celestia began to speak.

“Hello, Cadence. Twilight. Please, come forward. Luna and I have something very important for you this evening. Something that we have been preparing for a very long time.” As she walked forward with Cadence, Twilight Sparkle spotted something she had never seen before. It took several looks and a corresponding examination of the Lunar Princess before the importance of it soaked in, and several deep breaths once she had come to a halt on the balcony in order to ask the question that simmered below the surface.

“Princess Celestia. And Princess Luna.” Twilight swallowed, trying to vocalize the disbelief that held her paralyzed, but was unable to proceed before Cadence burst out with a giggle.

“Auntie Celestia! You're naked!”

It was true. The golden accoutrements that had been a part of the Princess of the Sun's regalia since before mortal memory were missing, leaving Celestia's mane unburdened and hooves bare. Even the golden peytral which Twilight could never remember not being around Celestia's neck was absent, with only the shortened hairs of her coat to show where it had once been. Princess Luna, even concealed within the shadow, appeared likewise unadorned, and Twilight jittered nervously on her hooves with little clicks and clatters on the balcony stone floor.

“Should we have taken our crowns off too, Princess Celestia? I didn't hear anything about it from Princess Luna—” Twilight shot a quick glance at the Princess of the Moon, who returned her look without changing her expression at all “—but we can if you want us too even though technically Cadence is the Princess of an Aligned Realm and as such can't be ordered to unless she's under arrest for High Treason which I don't think—”

“Twilight.” Celestia's voice was calm and strong as the mountain that Canterlot was built against. “Calm yourself.”

“Thou art a Princess of Equestria now,” said Luna, a tiny smile beginning to show at the corner of her mouth. “Thy stride must be such that all who see your demeanor know that the weights of the heavens are balanced upon you, and that no matter the circumstance, you are in control. Besides," added Luna with a sly smirk, “two naked princesses is a scandal. Four would certainly shake the foundations of reality and loose untold woes upon us all.”

Celestia rolled her eyes. “Quite well said, my sister. We have called you here for a far different purpose, but first, I would like you both to answer a question.” The Princess of the Sun walked over to Cadence and placed her long, fluted horn against the younger alicorn's only slightly shorter horn, lowering her noble head while her translucent mane flowed silently in the breeze.

“I remember when I brought you to the castle, Mi Amore Cadenza. My love, Cadence. For over nine centuries, I had become a creature of my habits, locked into rituals and routines such that at times I lost track of myself. There are still decades that I cannot recall, as I walked along the halls and spoke to the ponies who seemed as fragile as mayflies. Their faces would flicker, from young and eager servant to elderly retiree, and yet I would remain the same. There are places in the hallways I could show you where I walked in such unbroken lockstep over the years that I wore a set of dents in the granite. And then you came into my life, so young and yet so old at the same time. To protect myself from the pain of losing my sister, I had become like an oyster trying to protect itself from a sharp grain of sand, and in return, I found a beautiful pearl. Without you, I may have slumbered in my routine until Nightmare Moon was released and all would have perished because of my inattention. You awoke me from my grief with your love, and gave me the hope I needed. Tell me, Mi Amore. What am I?”

“You are the Sun,” said Cadence, lifting up her head to rub her nose along Celestia's. “You are the ancient and wise mare who took a foolish young alicorn under her wing and brought her into the world from isolation. I existed as a foal for many years, but I never lived until you showed me the light. You may not have been the mare who birthed me, but you have been everything that a mother could possibly be over these years, and I can feel the love you have in your heart for me that is indistinguishable from the love of a mare for her daughter.”

Ever so slowly, Celestia shook her head. “You are wise beyond your years, Mi Amore, and answer with your heart, but that is not the question I asked. Not who am I to you, but what am I, period?”

“Love is part of my nature, Aunt Celly. I can not separate who you are to me from what you are to the rest of Equestria, but I will try.” Cadence brushed her nose up the side of Celestia's face and nuzzled a floating piece of mane behind the Princess of the Sun's ear before taking a step backwards in order to meet Celestia's eyes. “I did not truly realize just what it was like to be a princess until I gained my own throne in the Crystal Empire. The crystal ponies do not just see me as their leader, but as an example of what it is to be a good pony. They strive much as I did when I was growing up under your wing. They want to be like me, much as I wanted to be like you, and still do.

“You are an example to us, a beacon of light that leads us into a better place like the sun. You are Equestria with every breath, the eternal and forever alicorn who has guided our country from the time of its birth, through times of wonder and times of extreme pain, even though you had to banish your own sister—” Cadence leaned over and gave a nuzzle to the nearby Princess of the Night “—you never gave up on her. No matter what doubts you may hold in your head, your heart tells the truth. She is your sister, now and forever, and shall always be at your side as a sister should.”

“Very nice, Mi Amore.” Celestia wiped a hoof against her face and took a deep breath before shaking her head and moving to one side where Twilight Sparkle was fidgeting.

Before she could say a word, Twilight blurted out, “Can I have a little time to do some research first, Princess. I mean Celestia. I mean… Please?”

After a brief snort of laughter, Celestia leaned down and rested her horn alongside Twilight's, adding a brief and almost motherly lick across her former student's nose. “Breathe, Twilight. This is not a test. I merely want to hear in your own words what you think I am.”

“You're not a changeling. Not that I would have cast the changeling detection spell on you. Or Luna. Although you both are acting a little weird. I suppose…” Twilight Sparkle closed her eyes and took a deep breath, holding it for a moment before letting it out with one hoof cast outwards and a relaxation of her shoulders. “What you are. Right. A summary, I presume. Canonical order or… Right.”

After a few minutes of relative silence, Cadence gently bumped against her sister-in-law. “Just relax, Twilight. I'd like to hear this too. What do you think Auntie Celestia is? What do you see with those perceptive eyes of yours that I don't?”

“That's… difficult, Cadence. She's different to everypony. A teacher would see her passing on her years of experience to all ponydom. The Royals see her grace and authority. A bricklayer sees the civilization she has helped build, a railroad engineer the network of rails she had caused to be laid to the edges of Equestria and beyond. An explorer sees her pushing the boundaries of the country to the vast unknown, a bookseller sees her stores of knowledge, a mother sees the way she cares for all of us as her own children and a child…” Twilight paused with her eyes still closed. “A child sees her bring the sunrise, and the new day given to them. They see the opportunity to fling themselves out into the world, to relish every drop of it, because eventually the sun will set again, and they will have to return home, to sleep in the embrace of night and dream of the new days yet to come. I can't really say what she is, only what others see in her…” Although she kept her eyes closed, Twilight Sparkle slowed and a wave of relaxation swept across her body. “That's it. She's a mirror who reflects better than any physical piece of glass. We don't see ourselves when we look at her; we see what we could be and what we can help others be.”

“Very astute, Twilight Sparkle.” Twilight opened her eyes to find the soft violets of Princess Celestia's gaze replaced by Luna's cool teal eyes. “My turn. Who do you believe I am?”

The ghost of a smile rose up in Twilight's cheeks and her eyes glittered like stars. “You are the Night, the gentle repose of rest after a day of hard labor. Your touch is gentle and loving, for the night is made for love and dreams of what might be. You are an infinite beauty of a nebula spread across the sky, and the heartstopping awe of a nova as the death of the aged stars give birth to new lights and fresh life. You are children, dancing beneath the moon and chasing lightning bugs through the summer night, and the brilliant silver of moonlit winter snow spraying out from under your skis as you plunge down the mountainside. You are the love of young ponies walking next to each other without words for hours under your light, and the aged widows who sit and look across the city in the night in mourning for lost loves. You are all the power and majesty of the moon and stars, touching our world but for a moment until you are gone again with the dawn.”

Celestia coughed once, with a faint blush rising in her cheeks. “Well, that's… very descriptive of you, Twilight.”

Luna turned and cocked her head to one side with a twinkle of joy in her eyes. “Jealous much, sister?”

It was Cadence's turn next to discreetly cough, looking a little embarrassed. “If you're going to ask me the same question, Auntie Luna, I think I'll have to use Twilight's answer. I really have not had the opportunity to be with you very much over the last year or so, what with all of my responsibilities in the Crystal Empire and getting married and…” Cadence ran a hoof over her still mostly-trim tummy.

“That is fine, Mi Amore,” said Celestia. “Now, I just have one more thing before we go. I wanted to make sure you both were prepared for this responsibility. I know this is short notice, but I believe it is best to do this without a lot of ceremony and emotional outbursts.”

"Best to do what, Princess?" asked Twilight Sparkle with a bright, alert grin. “Are you sending us on another adventure?”

“Not… exactly, Twilight.” Celestia lifted a hoof as if to gesture, then sat it back down again. “Do you remember the time I told you about immortality, and how it does not mean quite what everypony thinks it means?”

“Of course. You said that nothing is truly immortal, not even princesses. Everything has a beginning, and a middle, and an end, but princesses just have a very long middle." Twilight poked a gentle hoof at her sister-in-law and her expanding belly. “Some princesses have a longer middle than others lately.”

“Hey!” protested Cadence. “I'm eating for two. Or three.”

“Dozen,” said Twilight.

“Twilight,” said Celestia in that formal tone that always returned her student to a precise focus on the problem at hoof. “You are correct. Everything has its cycles. Children are born, they live, and they die. The seasons pass, the sun and moon rise, and even alicorns are subject to the immutable laws of nature. What I'm trying to say is… We have to leave. Soon.”

“What?” Twilight Sparkle quivered with tension, but Celestia continued before she could recover.

“Ever since the founding of Equestria, there has been an alicorn to raise the sun and moon. When my sister and I depart, I am glad to know my little ponies will be well cared for.”

“B-but what about training!” protested Twilight. “You can't leave! Princess Luna has shown me a lot, but there's so much more I have to learn! From both of you!”

“It is not the mind which determines your affinity with the heavens,” said Luna, stepping forward to stand directly in front of Twilight just the same as Celestia was standing in front of Cadence. “Your heart will guide you far better than any number of lessons we could give you.”

“Your hearts are pure as any who I have met during my long years,” said Celestia, beginning to glow golden in the light of the sunset. “There are no other ponies who I would trust with our powers. Farewell to you both. Do not think of us as gone, but only distant for a time. Guard well our little ponies, and do not let—”

“Sister,” interrupted Luna. “The schedule? We're going to be late.”

“Oh. Very well, then.” Celestia burst into a golden light so bright that everypony on the balcony was forced to close their eyes. “Princess Cadence, I give you my power over the sun. Use it well.”

The blinding light faded, and there were only three ponies on the balcony, along with a fading voice that said, "It is time, Princess Cadence. Lower the sun."

Fighting back the tears that had begun to run down her face, Cadence lifted her horn and spread her wings. Cascades of pastel flowed down her neck and tail, matching the fading colors of the sunset and curling around the golden crown that now sat behind her horn. A golden glow filled the balcony, much softer than the last time, and the sun gently slid beneath the horizon as if it were a well-trained pet.

“Twilight Sparkle,” said Luna's voice from the impenetrable darkness that now surrounded them. “My time is short also. You too must take my power and use it wisely. Guard well my stars, and let not the monsters of the night threaten our little ponies, or permit the—”

“Luna!” sounded a distant voice. “The time?”

“Oh, yes.” Luna coughed once. “Accept my power, Twilight Sparkle. Use it well.”

A darkness even more than dark surrounded the three alicorns on the balcony, and when it passed, there were only two. Twilight’s head was bowed, with her new mane of coiling darkness flowing around the black crown and cloth circlet around her neck. The swirls of stellar material combined with the few specks of light from the streets and paths below to provide a wan illumination that made the tracks of tears down her cheeks glisten silver.

The two alicorns on the balcony leaned against each other for mutual support in the darkness, quietly sharing the box of tissues. They did not speak or move for a long while except for the near-silent blowing of running noses and mutual mopping of damp cheeks.

“I c-can't believe they're gone, Cadence.” Twilight Sparkle turned to her sister-in-law while fighting back more tears. “Just like that.”

“Just like that,” echoed Cadence. “Auntie Celestia always told me that great changes either come very slowly or all at once. I don't think anypony could be ready for this, but I'm going to do my best. That's all any of us can do. I'm just glad I've got you at my side.”

“You're right, sis.” Twilight leaned against Cadence, breathing in and out deliberately as her impending tears gave way to the responsibility that had been pressed onto her. It was a heavy burden dropped on her without warning, but Celestia and Luna had trusted her, and she was determined to prove them right. “Without Princess Celestia and Princess Luna, we need to stick together like real sisters.”

“Darned right. I’m just glad I’ve got you.” Cadence wrapped up Twilight in a crushing hug and gave her a peck on top of the head. “First, you need to raise the moon. And don't give me any lip, or I'll tell your mother.”

“Well, if you pick on me, I'll tell my big brother.” Twilight sniffed a little and blew her nose on a tissue that Cadence floated over from a large nearby box, much as if Celestia had left them for just this occasion. “Thanks.”

“Don't mention it. What are sisters for? Big sisters, that is.”

“Really big sisters,” said Twilight. “Really, really, really—”

“Twilight.”

“Oh, all right. How does this sound? I'll raise the moon, then once have a good cry, we can go eat cake and break the news to the rest of the castle. It's going to be a lot of work. We've got some really big shoes to fill. Sis.”

“That sounds perfect.” Cadence smiled. “Little sister.”

Princess Twilight Sparkle arranged herself on the edge of the balcony with wings outspread and her horn lit with a dark glow. Ever so slowly, the moon rose up from below the horizon and the stars spread out across the sky, shining their light down on Equestria as they had for uncounted years.

---

On the tallest balcony in the Canterlot castle, two alicorns sat in perfect silence and watched the stars. Manes of lightest pastels and darkest indigo curled together on the tile floor behind them, making swirls of colors in the wan moonlight. The young alicorns even breathed in perfect harmony, staring upwards until the youngest one spoke.

“I'm going to kill them both.”

Twilight Sparkle’s voice indicated that not only had the speaker thought out all of the needed actions that would go along with the promise, but also which prison she would most likely be incarcerated inside and what the reading list for the years of her sentence would be. And worse, the absolute pure determination that her actions would be worth the consequences.

Cadence sighed deeply and put a wing around her sister. “Twilight, I know you're upset, but I've known Princess Celestia much longer than you have. She brought me into the castle when I was very, very young, and raised me at her side. We are as close as mother and daughter, which is why I’m going to kill her first. You can have Luna.”

“Sis!” Twilight turned to Cadence and put on her most pitiful begging eyes. “How about I kill them both and you can pardon me afterwards. We can have a nice laugh about it while out in the park with ice cream, just like we used to do when Shining Armor and you used to take me for walks. I’ll even buy.”

“Twilight, we can probably charge the ice cream to the Royal Treasury now.” Cadence folded her bottom lip over and returned Twilight's big-eyed pout. “Besides, I'm your big sister, and I know what's best for you. Killing them both all by yourself is just greedy.”

“But I'm an alicorn now, sis! I'm supposed to be greedy. All of those stars are mine now, and you just get one.” Twilight paused with one hoof pointing towards the star-strewn sky and its present configuration. “Not helping, is it?”

“Not a bit. See if you can put the stars back while I read the letter.” Cadence opened up the envelope she had found in the tissue box and read while Twilight looked up into the star-strewn sky and lit her horn. The huge words 'Happy April Fools Day' written across the night sky in stars began to shift under her attention as the stars reluctantly shuffled back to their proper positions, or at least fairly close.

“I think I've got an extra,” said Twilight Sparkle, staring up into the sky with an expression of divine annoyance. “Maybe if we found out where they went, I could drop it on their heads.”

“Mexicolt,” said Cadence. “Aunt Celly included their vacation itinerary, just in case there are any problems over the next—” her mouth twisted up in a brief frown “—three weeks.”

“Three weeks!” Twilight gave a sharp look to the leftover star and jabbed it up into a currently empty piece of sky. “How am I supposed to plead Temporary Insanity at my murder trial if they're going to be gone for three weeks? There are limiting factors involved here!”

“I think they intend on you calming down by then, Twilight. Besides—” added Cadence with a quick hoof-ruffle to Twilight's now glowing and shimmering dark mane “—that gives us three weeks to come up with some way to get them back that doesn't involve physical violence. I, for one, plan on moving into Celestia's tower and having it totally redone in that garish shade of fuchsia she hates so much.?” She cast a coquettish look at Twilight and batted her long eyelashes. “Do you want to help me pick out colt band posters to glue to the walls of her bedroom?”

“Do I?” Twilight grinned. “Sweetie Belle came up with a recipe for an unbreakable glue while trying to make oatmeal one morning. I'll buy a bunch of Boyz to Stallions posters, or even Blue Oyster Colt ones and we can stick them up together, just like when we were young. Then we can redecorate Luna’s tower entirely in rainbow colors!”

“Can you find any that glow in the dark?” asked Cadence.

“That’s so old fashioned.” Twilight grinned. “I can find paints that strobe in the dark.”

“This is going to be the most fun three weeks ever,” squealed Cadence. “Auntie Celestia left us with the Cosmic Credit Card and we get to go shopping!”

“And I plan on buying out the Branch and Stables bookstore, from the foals section all the way back to travel," gloated Twilight. "We're still missing something, though.”

“What do you mean?” asked Cadence even as a curl of her glowing ethereal mane drifted across her face and into her mouth. “Phhffft! Oh, I see.”

“All the powers of the alicorns and three weeks to use them,” mused Twilight. “I wonder… What do you think Shining Armor would look like with wings?”

“Ohhh…” Cadence broke into a broad smile. “I like the way you think, little sister.”

“Right back at you, big sister,” said Twilight. “Let's get started.”