What if, at the end of the Friendship Games, Sunset Shimmer took all the magic and went home? What if that changed her world completely? What if she wanted to know what might have happened if she hadn't made that choice?
Sunset Shimmer has returned to Equestria with all the magic of the Elements of Harmony inside of her, traveling by accident ten years back into the past. Nearly all-powerful, but far from confident, Sunset questions her choices... and most of all, the possible consequences of her action. In particular, will the changes she's made to the timeline prevent her best friend, Princess Twilight Sparkle, from achieving her own destiny as an Alicorn?
What's an all-powerful Alicorn with a talent for magic supposed to do about it?
An unofficial crossover between LordBrony2040's "Sunset Reset" and a "Canon" Equestria Girls / MLP timeline. (At least until Sunset changes things, again.)
Princess "Mi Amore" Cadenza, otherwise known as Cadance (or Princess Cadance at most) to her friends, was starting to get worried. Every night for a week, Sunset Shimmer had slipped out of the Alicorn sized bed she and Cadance shared with their coltfriend, Shining Armor, after Shining had drifted off to sleep and then had been missing for nearly an hour before slipping back into bed.
It wasn't as if Cadance wasn't used to Sunset putting in some late night work, either drawing up new legislation or working on some new invention, usually inspired by her time on the world of humans she'd spent nearly three years living in while in self-imposed exile from Equestria, but USUALLY Sunset would stay in their apartments, the faint light from her horn and the rustling of books and papers, quill and ink being something that had started to become almost relaxing to the Alicorn of Love.
But whatever Sunset was up to this week, she didn't want anypony else to know about. Cadance had tried to follow her, but Sunset had apparently been teleporting away from just outside their room, and Cadance didn't have the skill to track a teleport, even though she knew, from what Celestia and Sunset both said, that it was possible.
She could go to Celestia, of course. While the eldest Alicorn in Equestria certainly had the skill to track down her adopted daughter, Cadance didn't want any reason to cause any more issues between the two hot-headed solar alicorns. Things between Celestia and Sunset had been intense ever since Sunset had returned to Equestria as a full-fledged alicorn... one more powerful than Celestia herself by a significant margin. Not that 'returned' quite fit the unusual circumstances of her ascension. One moment, Sunset Shimmer was looking into Starswirl's mirror portal, the next, with a flash of light, she'd apparently transformed into an Alicorn.
The truth was somewhat more complicated. Cadance felt her head hurt just thinking about it. Somehow, Sunset had traveled back in time to a month before she'd left through the portal in the first place, making the events that would cause her to flee through the portal in the first place never happen. The only pony who could remember the events of that alternate timeline were Sunset herself. Not that Cadance doubted Sunset's explanation. Not anymore. Too much evidence had piled up to show that everything really had happened the way Sunset remembered it. It wasn't Sunset's recollection of events that Cadance doubted, it was her interpretation of the reasons behind them... and of the motivations of Sunset's "best friend" in that alternate timeline. Princess Twilight Sparkle.
In the end, while gravely tempted to pass through the portal back to the human world in an effort to try and set things up so that her presence in their world wouldn't prevent Twilight Sparkle from becoming an Alicorn and a princess, Sunset Shimmer had agreed to stay. She'd become such a huge part of so many ponies lives and Cadance had managed to persuade her not to leave, arguing that her leaving would cause more harm than her staying.
Cadance herself was incredibly happy that Sunset had chosen to stay, not in the least because that meant that the mare that she had fallen so madly in love with wouldn't leave her. She, Sunset, and Shining Armor had somehow stumbled into a three-way relationship that was, as far as Cadance knew, unique in Equestrian society. They were partners... each to the other. Cadance loved Shining Armor AND Sunset, who loved Sunset and her, who loved her and Shining. They each had their own unique relationship with each other, but, with work and care, they managed to balance their odd relationship into something that Cadance found incredibly fulfilling and rewarding.
But being in love didn't solve everything, especially not for a mare as complicated as Sunset Shimmer. Sunset still carried a great deal of guilt over her supposed crimes of the past... over the wrongs she had committed before learning, as she put it, about the 'magic of friendship', and she still had huge issues with self-doubt and self-loathing. She found it incredibly difficult to believe that she deserved to be happy, and Cadance made a point of ensuring that Sunset knew that she was loved and valued every single day.
Whatever Sunset Shimmer was working on, she didn't want anypony else to know about, and that worried her. It wasn't that Cadance didn't trust Sunset. She knew implicitly that Sunset would never deliberately harm her, Shining, or anyone she cared about, but that didn't mean Sunset wasn't capable of harming them indirectly by a misguided desire to punish herself... or to try and "fix" something that shouldn't be repaired. If Sunset Shimmer insisted on hiding her actions, there wasn't much Cadance could do to stop her, but that didn't mean she shouldn't try.
Slipping out of bed herself, careful not to wake Shining Armor, Cadance went to the entry hall to their room to wait for the love of both their lives. If she was right, Sunset wouldn't be very long. Opening a book on Crystal Magic that she'd been studying for the past few weeks, Cadance settled down to wait.
*********************
It seemed longer, but a glance at the clock told her that it had been just a little bit more than an hour when Sunset slipped quietly through the door from the Castle hallway outside into their entry hall, obviously intending to head back to bed.
"What's going on, Sunset?" Cadance asked quietly. "You've been sneaking out every night for a week now. What are you working on that you don't want to talk to us about?"
Sunset started slightly at Cadance's voice, and her slightly wide eyed look told the pink Alicorn that she hadn't noticed Cadance waiting for her. "Working on? Er..." Sunset's eyes shifted up and to the right, and Cadance sighed.
Cadance frowned. "Please don't think up an excuse. If you don't want to tell me, you don't have to, but don't come up with a lie. You owe me better than that."
Sunset sighed and hung her head. "I know... I just. I don't think you'd really approve of what I've been doing."
Cadance raised an eyebrow. "That doesn't sound good. But you know you can't just leave it at that. I'll worry more if I have to guess."
Sunset took a deep breath and nodded. "Yeah. I know. It's not like I'm doing anything bad or anything. It's just I know you don't like the idea of me messing around with the Mirror Portal."
Cadance's eyes went wide. "You're right about that! Sunset! What are you thinking? You can't possibly intend to go back to the human world, not after everything..."
Sunset quickly shook her head. "No! No... I know that I nearly did that before, and I'm sorry about that. I know I can't put everything back to the way it was, and I really don't want to leave you and Shining... and mom, and Twilight and the girls. And I know that if I left it'd hurt all of you. So no, I'm not planning on going anywhere."
Cadance looked confused. "So why? What good does messing with that mirror going to do you?"
Sunset shrugged. "Well, I started thinking about how to fix the main thing I've been worried about ever since I came back. That going back in time and becoming an Alicorn, I may have jeopardized Twilight Sparkle's chance to become an Alicorn... and a Princess. I know I'm already planning on helping her as much as I can, but how do I know it'll be enough? Becoming an alicorn isn't as simple as I used to think. Mom can't just poof wings on ponies who she thinks deserve it. It isn't about magical aptitude, or, no offense, you'd never have become one."
Cadance laughed. "None taken. I know I'm not the magical prodigy you or Twilight are."
Sunset smiled. "And it can't just be about being a wonderful pony... or I wouldn't be one either."
Cadance frowned at her lover and nearly growled. "You ARE a wonderful pony, Sunset. Although I think you're right. If you have to be some perfect, kind and caring, infallible wonder pony, Celestia certainly would never be one."
It was Sunset's turn to glare at the smaller alicorn, who bore the Amber alicorn's ire with aplomb. "Mom may not be perfect, but nopony is... and mom has done things nopony else could have managed. Holding Equestria together for a thousand years...."
Cadance held up a hoof. "Nopony is saying Princess Celestia hasn't been a fantastic ruler for a millennia. And It'd be hard to find a pony who cares about her subjects more. But she's nowhere near perfect."
Sunset rolled her eyes, then nodded. "Right... so becoming an Alicorn isn't as simple as being powerful, or skilled, or even just being a good pony. There's something more to it. I want to make sure that I can guide Twilight down the right path to her destiny. I KNOW she'll be a wonderful alicorn someday."
Cadance looked confused at that. "OK, that part I understand, but what does that have to do with the mirror? Do you plan on having her look in it, so she can see her destiny? I mean, we know how well it worked out for you..." Cadance trailed off. "Well, I guess in the end it worked out pretty well. I mean, you saw yourself becoming an Alicorn in the mirror, and eventually that's exactly what happened. From our perspective, you became the alicorn you saw the instant you looked in the mirror, even if you had to take the long way round on your own."
Sunset frowned. "Well, I thought about that... I don't think mom would be thrilled about having Twilight look into the mirror like that after what happened to me, but I figure I could probably convince her it was worth it. But no, that wasn't what I had in mind. I've been doing some research on Star Swirl's work in temporal and dimensional mechanics, and I've think I've almost got it worked out."
Cadance blinked. "Got what worked out?"
Sunset grinned. "How to talk to Princess Twilight Sparkle herself, that's what!"
"WHAT!?!" Cadance shouted loud enough to be heard throughout the entire wing of the Castle before putting her hooves over her muzzle in embarrassment.
Sunset frowned at her. "I know you have this theory that Princess Twilight purposely kept me from returning to Equestria... but she's a good pony. She was my best friend in that timeline. I really miss her. I don't know for sure why she didn't respond to me during the Friendship Games, but I trust her. She wouldn't have done that to me."
Cadance raised an eyebrow dubiously then shook her head. "Our Twilight is a wonderful filly, but..." she sighed and shook her head. "No... never mind. I know you won't accept it without proof. Maybe talking to your Princess Twilight Sparkle IS a good idea. I'd like to hear her explanation for abandoning you like that for myself."
"She didn't abandon...!" Sunset started to protest.
"I don't want to fight with you about this, Sunset." Cadance interrupted with a sigh. "In any case, I'll help you with this, if I can. What do you need to do exactly?"
"Girls? What's going on?" Shining Armor's voice was as sleepy as the colt himself looked, still a bit mussed and dishelved from sleep as he opened the door to their bedroom.
Cadance winced. "Shiny... I'm sorry, I didn't mean to wake you."
Shining Armor closed his eyes, took a deep breath, and seemed to gather himself, and when he opened his eyes, he was looking much more alert and awake. "Well, something's obviously bothering you. Is there anything I can do to help?"
Sunset sighed. "Honestly, I think I'm on my own with this one. The only thing I still need is mom's journal. The one she used to communicate with me. Mine isn't around anymore... but I have a pretty strong theory as to WHY."
Shining Armor blinked. "Princess Celestia's journal?" He shook his head, as if shaking away his lethargy. "Right... you said something about that. You and Princess Celestia had linked journals, if either of you wrote in one, the writing would appear in the other. But what do you need that for?"
Cadance hesitated a moment, then made a decision. "Sunset wants to talk to Princess Twilight Sparkle. The one that she met in the other timeline."
Shining Armor blinked. "Princess?" His eyes widened as memory returned. "Right, right... while Sunset was on the human world, my sister became Princess Celestia's student, and then an Alicorn. Right?"
Sunset nodded. "When I came back to Equestria the first time, I stole her crown, and took it back to Earth, and tried to use its power to raise an army to come back and conquer Equestria. But Twilight followed me through the portal and stopped me, saved those poor kids from me...."
Cadance cut in. "You said yourself that the magic in that crown turned you into a monster... you weren't in control of yourself."
Sunset snorted. "That's being generous. I put it in motion, and I was the one who turned herself into a demon. It was my anger, my jealousy, my skill with magic that made me into her. Maybe I wasn't thinking clearly with all that magic going through me, but it would have been my fault. I nearly killed..." she choked. "I nearly killed her Shining. I nearly killed Twilight. If it wasn't for her friends... my friends, she'd have died. They saved her... the magic of friendship saved her."
Shining Armor blinked. "The magic of friendship?"
Sunset shook her head. "I still don't fully understand it. But the magic of friendship is the most powerful magic I've ever known. Honestly, Generosity, Laughter, Loyalty, and Kindness create a magic stronger than any other. Twilight and those five girls formed a bond in just a few days strong enough to stop me, to return me from my demon form, undo all the damage I did..." she chuckled. "Well, it DID leave a big hole in the front lawn of the high school... but otherwise..."
Shining Armor shook his head. "You told us about this before, but I still can't believe that MY little sister made friends with five strangers that fast. And that they somehow created magic on a world where there wasn't any?"
Sunset shrugged. "Well, Twilight's crown was the initial source of the magic in that world, I think, although, now that I think about it, she said that the magic of friendship was in their world AND ours. I don't think they'll be able to do magic without the trigger of the crown, but..."
She shook her head. "No, I felt it when I left. Applejack, Rainbow Dash, Fluttershy, Rarity and Pinkie Pie... when I took their magic, I could feel it. I took every bit, even the spark of magic left by their interaction with Twilight's crown. Without that spark, they'll never get magic working in that world again." She sighed. "I'm still not sure I made the right choice there. Magic was dangerous on Earth, sure. And it was really unpredictable... and if the wrong people there found out about it, it could have been really bad. But was it really my call to make? I just don't know."
Cadance moved over and gave her a hug. "I know you did the best you could, Sunset. You cared about those girls. You still do." Not that they deserved it.
Sunset sighed heavily. "Actually, that's kind of one reason I want to do this. If I can talk to Princess Twilight, maybe she can get a message to my friends as well. I obviously left my journal in their world when I left..."
Shining Armor shook his head. "Wait, this is the part I don't get. How do you talk to Princess Twilight? I mean, even if you could talk to my sister in the future... which I'm not saying you couldn't figure out, didn't you change the timeline? Isn't the fact that you changed history the reason you wanted to go back to... err... Earth in the first place?"
Cadance nodded. "Right. That Twilight Sparkle, that future, never happened. You changed all that."
Sunset Shimmer wrinkled her nose. "Well... yes and no. You see, that night I tried to go back. The night I went down into the vault to try to go back to Earth... and our Twilight accidentally broke the mirror? We saw Canterlot High School... but not the version that I ended up in when I first went through the portal, but Canterlot High School only minutes after I left for the last time. Mom said it. Time isn't a constant across dimensional borders. That's part of what I've been working on for the past week, working on Star Swirl's time and dimensional equations. When you go to a different dimension, you can, in theory, emerge at any particular point in their timeline."
Shining Armor looked surprised, then slowly started to nod. "OK, that actually makes sense. I mean, you said you were in that world for almost three years, but the Twilight you met was only a couple years younger than you, right? So while you were in the human world, at least ten years must have passed here in Equestria. Right?"
Sunset looked surprised, then pleased. "Right! Nice bit of deduction there, Shiny."
Cadance shook her head. "Well, I don't get it myself, but I trust you when it comes to magic, Sunset. So the mirror can go back and forward in time?"
Sunset looked thoughtful. "In theory. In practice, not so easily. It uses a lot of the same equations that Star Swirl used for his Time Travel spell... and that only takes you back one week, and creates a closed temporal loop. No paradox. You can't rewrite history with Star Swirl's spells. Or at least, I thought you couldn't. But somepony else DID."
Cadance blinked. "What do you mean 'somepony?' Wasn't it you that changed history by coming back in time?"
Sunset shook her head. "I simply went through the portal with the intention of coming home. At the time, I thought I felt a weird temporal signature affecting the portal, and obviously, that was the case, and we have a few clues regarding it. We know that SOMEPONY rewound time in all of Equestria while I was on the other side of the portal. The reason there weren't two of me in the room was because when time was rewound, I wasn't in Equestria at all. The spell didn't include me. If I hadn't traveled through the mirror when I did, the other me would have simply vanished. I'm honestly not sure WHAT would have happened... but that's the most likely scenario that I can come up with."
Shining Armor raised a hoof. "Wait... who cast the time spell that rewound time in all of Equestria? I mean... not even you've ever done anything that powerful."
Sunset frowned. "I don't know. It's a problem, because whoever did it could do it again. I've put up warning spells and a failsafe just in case somepony tries to rewind time again, but I'm not sure they'd even work. I've never even heard of a spell that could do what must have been done. Still, it's theoretically possible. You'd need an insane amount of magic... probably even more than I have right now, but it's possible." She wrinkled her nose. "That's one thing I want to talk to Princess Twilight about, actually. She's easily as smart as I was at her age, probably smarter, and Princess Twilight is from at least ten years in our future. She might know more about temporal and dimensional magic than I do, and at the least, she might be able to come up with something to help."
Cadance raised a hoof. "Wait... I don't understand. Maybe things haven't changed on the other side of the mirror portal... it's still right after you left over there... probably. But, Equestria was still rewound, right? Princess Twilight would have been rewound along with everypony else."
Sunset nodded. "I thought of that. In fact, when I first started working on this problem, I was sure that's why she never responded to me when I sent her messages through the journal during the Friendship games. Because she'd been rewound. She didn't respond, because she wasn't there anymore. But I've been working on the equations, and I think there's a chance, a very good chance, that that reality... the one where Twilight Sparkle is the Princess of Friendship, still exists. You see, there's a theory I heard about in the human world... multidimensional theory, actually. It suggests that every time you go back in time and make a change, you create a new dimension, splitting it off from the original. Well, it's more complicated than that... and believe it or not, Starswirl's time spells actually take that theory into account, or at least, the possibility. Starswirl's time-traveling spell specifically prevents you from changing time. If you use his spell to travel back in time, it turns out everything you did was destined to happen. You can't change anything."
Cadance blinked. "But things DID change, right? You remember a history that never happened here, so history can be rewritten."
Sunset nodded slowly. "Which means, it's possible that the spell split off another dimension when it rewound time. So Princess Twilight could still exist... in an alternate dimension."
Cadance frowned. "But it's also possible that the spell just reset everything, and that timeline is simply gone, right?"
Sunset wrinkled her nose. "Maybe... but just the existence of the human world proves that other dimensions exist. In fact, from my research, I know that Starswirl found more than one. Some of the dimensions he found were apparently pretty similar to our own! The problem was, the more similar they were, the thinner the walls between worlds. So going back and forth to a dimension really similar to our own could, in theory, collapse the walls between worlds and cause them to merge."
Shining Armor grimaced. "That sounds bad..."
Sunset shrugged. "Well, actually, I think that's one reason time isn't really messed up already. I mean, if the theory is sound, then there could be infinite alternate dimensions, where everything that COULD have happened, DID happen. But Starswirl only was able to travel to dimensions where the differences were pretty major. My working theory is that unless the difference is pretty big... like, say, a new Alicorn spontaneously being created where one didn't exist before, then the dimensions can merge really easily... and they probably do exactly that... so minor changes... we'll call them tears, minor tears in time just... fix themselves. The dimensions merge and small divergences just work themselves out so that time stays on track."
Cadance blinked. "But you coming back as an Alicorn was a BIG change, right?"
Sunset nodded eagerly. "Right... so if I'm right, the Princess of Friendship, Twilight Sparkle, still exists, and so does that version of Equestria."
Shining Armor shook his head. "I can't believe that Twilight becomes the Princess of Friendship. I mean... Twilight? Princess of Books, or Magic, or something... but Friendship?"
Sunset smiled softly. "Twilight taught me what friendship means. Well, her and my friends on Earth. I'm not saying she was perfect... she was scared sometimes. She didn't always know what to do. But she understood the power of friendship like nopony I've ever met. She believed in me, and gave me a second chance when I never deserved one. You'd be proud of her, Shiny."
Shining Armor smiled. "I am proud of her. I always have been."
Cadance was silent. What do I say? That I think Sunset's Twilight Sparkle was jealous of Sunset Shimmer's connection to Celestia and purposely left her there? Sunset doesn't believe that, and I CAN'T say that to Shiny. It'd kill him to hear that his cute little baby sister did something like that.
Sunset took a deep breath into the silence that followed. "Anyway, we already have a connection to the world where I lived as a human. In fact, it's the same one Princess Twilight used in order to open the mirror early when we had to deal with the Sirens. Princess Twilight used the connection between the journals, Mom's and mine, that is, to open the mirror early. It shouldn't be TOO hard to replicate that. After all, if I'm right, my journal is still on the other side."
She scratched her head sheepishly with one hoof. "Honestly, I can't believe I forgot about it. I meant to take ALL the magic out of that world, but I left one bit behind. That journal. It wasn't anywhere near when I closed all the breaches and took the magic from the girls and Spike."
Cadance caught on at that point. "And that journal is still linked to Celestia's journal here, right?"
Sunset nodded. "It should be. Mom showed me it the night I had decided to leave. For some reason, it took nearly a week, but it updated with everything that Twilight and I had written to each other since I used it to call for help against the sirens."
Shining Armor looked confused. "Wait. Even if you COULD send a message to the alternate world where Princess Twilight Sparkle is, she wouldn't be a princess there yet, right? She's still just a filly. It'll be years and years before she's a princess, there OR here."
Sunset shook her head. "Don't you remember? Time isn't a constant when traveling through dimensions. The only reason that time seemed to move forward at the same pace for me and Twilight after I first stole her crown was that there was a constant back and forth of magical energy after that point. My friends, Applejack, Rainbow Dash and the others, they had a connection to Twilight's crown... which was on the Equestrian side of the dimensions. Just like the Journals had a connection despite being in separate worlds. Now, when mom and I stopped using our journals, time started to split apart. Ten years passed here where less than 3 passed there, but after I stole Twilight's crown, the amount of energy that must have been passing through the portal constantly... must have kept the dimensions temporally aligned, so time for me and Princess Twilight passed about the same. Until I took all that magic away, anyway."
Shining Armor slowly nodded. "OK... so, time isn't a constant between dimensions unless magic makes it... er... constant?"
Sunset Shimmer nodded enthusiastically. "Right! But once I took the magic that connects our dimensions, time started passing differently again. I figure that time passes a LOT slower in the human world. That would explain how the Celestia there is only in her thirties, instead of over a thousand."
Cadance blinked. "Wait, what?"
Sunset went on, ignoring Cadance's confusion. "So, in theory, while the connection between this world and the world of the humans is now down to just Starswirl's mirror and my mom's journal, time's going differently here and there. The portal is closed now, and we aren't using mom's journal as a connection either. So we're temporally unlocked from each other." She waited for one of her lovers to respond, but this time she just got puzzled stares, so she continued. "Anyway, if Princess Twilight Sparkle is in a dimension that got split off from this one, that means she has a copy of Mom's journal as well. So we're both connected through that journal... in theory."
Cadance blinked. "What... do you mean you could just write in Celestia's journal and Princess Twilight will be able to see it?"
Sunset looked thoughtful. "Maybe... but even if my splitting the timelines... well, me and the mystery pony that rewound our Equestria, even with that, I'm pretty confident that I should be able to establish a connection between the journals even if it's failed for some reason. Assuming my theory is correct, anyway."
Cadance sighed. "So that's why you need Celestia's copy of the journal."
Sunset nodded. "Yup."
Shining Armor shook his head. "Wow. I can't believe you worked all this out in just a few weeks."
Sunset looked a bit guilty. "Well, technically I may have cheated a bit. You see, I didn't want to stay out all night, since I knew you'd worry, so whenever I went to the Starswirl wing to study, I cast that time dilation spell I showed you to give myself more time to study. And... er... some extra time to nap and stuff. It's been so crazy recently, I needed the extra sleep, to be honest. So I've actually been working on this for close to a month... relatively speaking."
Cadance glared at her, then sighed, shaking her head. "I really wish you wouldn't do stuff like that without telling us, Sunset. We'd have helped if you told us first."
Sunset smiled sheepishly. "Well, I had no idea if it'd even work... and no offense, but neither one of you has the background in temporal mechanics and dimensional magic that I do. Mom might have been able to help, but..."
Cadance laughed. "Yeah, trapped in a time bubble with your mom for days at a time? Probably wouldn't have been pretty."
Sunset grimaced. "We're getting better."
Cadance sobered, then nodded. "I know. Still, I guess you had your reasons. You WERE planning on telling us this once you'd worked it out, right?"
Sunset hesitated. "Yes. I wanted to give you a chance to talk to Princess Twilight anyway, Cadance. You'll see that you were wrong about her. She really only wanted the best for me."
Cadance glanced at Shining Armor uncertainly, then shrugged. "I'll try and keep an open mind. But... I'm guessing you could use some help with the next part?"
Sunset sighed. "Yeah, convincing mom to let me borrow her journal." All three of them winced.
