All things considered, today was a fairly unremarkable day in the town of Canterlot. Oh, to be sure, there were plenty of things happening, but none of it seemed that out-of-the-ordinary. The people in the streets were as busy as ever, there was plenty of pleasant weather about, and as for the local school, Canterlot High, all of the students there were simply going about their business. Very little about this day seemed to suggest that anything big or unexpected was about to occur. And yet, amongst this all, there was one solitary figure that seemed out of place. Sunset Shimmer, former student of Princess Celestia, was currently standing outside the still-ruined remains of the school's once-famous horse statue, staring at its base, as if expecting something. Sure enough, her waiting didn't take much longer, and before she could react, the base shimmered, resulting in a new figure emerging. Sunset broke into a smile as the figure stood there, brushing herself off, before finally breaking the silence.

"Good to see you again, Twilight."

Twilight Sparkle, the Princess of Friendship herself, now stood before Sunset, smiling just as sweetly as she always did. Not further words passed between the two girls for the time being, and instead, they simply walked closer, embracing one another in a friendly hug. A few moments passed before they finally parted, and when they did, Sunset, as usual for her, got right down to business.

"You said you had something important to tell me?"

With a look of determination upon her face, Twilight nodded.

"I do. But don't worry, it's nothing earth-shattering or apocalyptic or anything like that."

Despite the seriousness of such a prospect, Sunset couldn't help but give out a small chuckle.

"That's good. I think three is this school's limit."

Much like her friend, Twilight let out a brief laugh, one that Sunset soon joined in on, and when it finally died down, the young princess gestured to the nearby street. Getting the message immediately, Sunset nodded, and before long, both girls were off, walking at a fair pace down that road. For a few minutes, things were silent, as Twilight very much looked like she was getting her thoughts in order. Knowing her well enough to recognise this, Sunset gave her all the time she needed to do just that. When they came to the street corner at the end of the road, Twilight finally spoke up, turning to Sunset as she did so.

"Sunset...do you remember what I told you the last time I was here?"

Looking to her, the former unicorn gave a nod.

"Sure. Time travel, an angry mare out for revenge, all that stuff?"

Twilight nodded back, looking ahead as the two finally crossed the road, continuing to speak as she did so.

"That day...it's got me thinking. More than usual actually."

To that, Sunset let out a momentary laugh.

"I don't blame you. Going to the past, visiting other worlds...it'd make anyone ponderous."

Although she smiled back at that remark, Twilight nevertheless remained thoughtful in both her expression and her tone of voice.

"I know. It's just...it actually got me thinking about...well...this world."

Hearing that, Sunset stopped, looking to her friend with curiosity.

"What do you mean?"

Now stopping herself, Twilight turned to Sunset and let out a sigh, before starting to explain things.

"Sunset...if you were to look at this world, and I mean really pay attention to it...how would you describe it?"

Needless to say, Sunset was rather taken aback with such a question. But, regardless of her feelings on the matter, she nevertheless tried to answer, looking around at their surroundings. She took in everything, from the other people walking about the street, to the nearby shops, to even the sky above them. When she was done, she looked back to Twilight, giving a quick shrug of her shoulders before giving her answer.

"Well...I know it was strange at first for me to live here...but it just seems like a normal place."

Twilight nodded before replying.

"I understand that. But what strikes you as odd about it? Something you think of as strange when you think of this world and Equestria?"

Again, Sunset was unsure of where this was going, but, as before, still tried to give an answer.

"Well...I suppose if I had to put my finger on one thing I find strange...it's that we all have counterparts. Every pony in Equestria...there's a human version of them on this side of the mirror."

To that, Sunset started really thinking on her words.

"It's like...like..."

It took a while, but, after some serious thinking, Sunset's eyes began to widen, looking as if she'd just realised something important or shocking. Soon afterwards, she turned, looking Twilight right in the eye. Seeing her friend's expression, the young princess knew that they were of one mind on this.

"Exactly. It's like Equestria...but different."

After a few moments of silence, Sunset started shaking her head.

"Twilight...you're not suggesting what I think you're suggesting...are you?"

Giving a small smile, Twilight nodded.

"I am. Sunset...I don't think this world is, or ever has been, another dimension."

Turning, the alicorn-turned-human looked around at their surroundings, from the shops, to the road to everything in-between.

"I think...that what we're standing in...is an alternate timeline, like the ones I saw when fighting Starlight."

As one would expect, Sunset now looked to the princess with utter shock, taking a step backwards and, like her, starting to stare intently at all the things around them. The look on her face was that of one who had never truly seen their surroundings before, as the prospect presented to her began to sink in. But, even now, there were doubts in the former unicorn's mind, which she was more than willing to voice.

"But...but...it can't be! This world is about as different from Equestria as you can get! There's no ponies, no magic no...no ..."

But, she was halted by a raised hand from Twilight.

"I understand that this is difficult to accept, but consider. Many of the alternate timelines I visited were starkly different from the Equestria that you or I know. A world of constant war. A world of eternal night. A world where there is not even any life at all."

Looking to Sunset in earnest, Twilight narrowed her eyes slightly.

"Is it really so hard to imagine that, if such worlds can be made from altering one event from one pony's life...that a world as different as this one could have been made by another change in events? Perhaps during the very conception of the world itself?"

Twilight turned, again looking at the town around them.

"A turning point at the very dawn of the world. One that made two worlds on opposite ends of the same spectrum. A change or choice that split history in two. One leading to a world of ponies and magic, and the other...leading to a world with neither."

Sunset stood there, utterly flabbergasted by what she'd just heard. And yet, despite her best efforts, she had no response, at least not one that could outright refute Twilight's theory. As for the princess herself, she saw the doubt on her friend's mind, and began to speak softly to her.

"There is one other clue that might actually lead you to believe this."

Sunset looked to her, with a look of curiosity that gave Twilight all the permission she needed to continue.

"This world and Equestria, much like the myriad worlds that I went to...are connected by powerful magic. Specifically, the magic mirror. But, that artefact lay unused for centuries, until you and I came along."

Taking a step forward, Twilight gestured to her friend before speaking up again.

"Think, Sunset...who is the one figure in Equestria's history that was known to use that mirror, and may have even had a hoof in its creation?"

Sunset stopped to think on that for a moment, before giving Twilight her response.

"It was...Starswirl. Starswirl the bearded, if the legends are to be believed."

Twilight nodded.

"Exactly. He knew of this mirror, and while he himself may not have come here, he at least knew that some other world existed on the other side of it. He must have done, or else he wouldn't have known to send Adagio or her sisters here all those centuries ago."

Sunset nodded, unable to really argue with that, but stayed silent as Twilight continued.

" Now, ask yourself this. What else is Starswirl known for?"

Again, Sunset considered that, and when she'd finally come up with an answer, her expression became one of shock, one that led to Twilight giving a smile and a nod.

"Exactly...time travel. Maybe, just like Starlight proved, he was more successful in creating time magic than he first thought. Maybe, in his efforts to create and harness such magic, he unknowingly created a gateway to an alternate timeline. Just like how the magic of the cutie map could create gateways to the other alternate timelines."

Sunset stood there, mouth agape, and turned, looking upon the ordinary-looking homes and streets around her, before finally speaking quietly to herself.

"This world...was Equestria? All this time?"

Sighing, Twilight took a step closer, placing a hand on Sunset's shoulder, gaining her attention.

"I want you to know that, at this point, it's just speculation on my part. But, given everything I've learned, of this world, of time magic and everything else...well..."

Before she finished speaking, she watched as Sunset nodded, giving her a friendly smile and looking far more relaxed than she was a moment ago.

"I understand. It's...it's an incredible thing to consider."

To that, Twilight smiled right back.

"Yes it is."

Turning, the two girls looked out at the world around them, with Twilight being the one to say what was on both of their minds right now.

"Our worlds...Earth and Equestria...not as far apart as we first thought."