The party only lasted until about midday, giving Sunset ample time to visit her family in Canterlot before the day's end. Twilight and Pinkie guided them to the Ponyville train station, Pinkie conversing with Midnight about what sort of party conventions existed in the human world. Twilight, on the other hoof, was discussing something far more important with Sunset.
"Are you sure about this?" she asked as they trotted along.
"Absolutely," Sunset replied despite her nerves. "It's been too long, and I have a lot to account for. They at least need to know why I won't be around."
Twilight fell silent for a moment, carefully phrasing her next query. "Will you ever return for good?"
"I don't know if I could anymore. I've spent so much time and effort in making a new home on the other side that I don't think I have a place here. That and I can't just abandon Midnight, and I highly doubt she'll be willing to give up everything she's worked towards for a fantasy realm of pastel-colored magic horses."
"So what are your plans, then? The human world doesn't seem like it has much to offer in terms of your potential."
Sunset chuckled. "I'm getting a slight sense of deja vu. Pretty sure it was just a few days ago I was having this conversation with Midnight."
"Great minds think alike." Twilight joked.
"Since when did you get an ego?" Sunset asked before sighing softly under her breath. "I don't know what I'm going to do. For now the plan is to help Midnight with whatever she plans to do, and try and prevent any magical apocalypse." Sunset glanced towards Twilight. "Speaking of, what's your idea with the portal anyway?"
"Oh, right! I'm waiting for Starswirl to return from an excursion so he can study the portal and perhaps tell me what might be going wrong with it."
Sunset's eyes widened as the name-drop dawned on her. "Wait, Starswirl? As in Starswirl the Bearded??"
"The very same. We freed him and the rest of the Pillars from Limbo about a month back."
Sunset hung her head in defeat. "Why do you always have to do the impossible?"
Twilight smiled to herself. "it's a natural gift."
Sunset couldn't remember the last time she had ridden a train. Almost everybody in the human world used cars or motorcycles, and while they did have trains, Sunset had never ventured far enough outside of the city to ever require one.
Midnight, however, was absolutely fascinated by the locomotive; more specifically, its ability to function without input from a conductor or technician. She surmised a spell determined its destination, and said spell would be recast at every stop. Sunset was only half paying attention to her theorizing, though, simply content to let her throw out ideas during the trip while she contemplated what exactly she was going to tell her family. I only hope they still live in the same home.
It was a relatively short trip, and before long Sunset found herself wandering the familiar streets of Equestria's capital.
Despite her time away from the city, she still managed to remember her away around, even able to point out where some buildings no longer stood or where new ones had been established. It became even easier as they approached her old neighborhood.
Midnight wasn't as keen on the city as her girlfriend. While the architecture was certainly something to marvel, and the sheer number of unicorns performing magic was something she always delighted in seeing, the general color palette of the city was perhaps a bit too conformist. Almost every building had a similar color scheme of white, gold and purple, and it only served to make her appreciate the more unique buildings over the simplistic homes.
Sunset's home, however, was something else. Midnight never expected that one small change could mean so much, but the simple act of changing out the traditional violet for a bright orange gave her abode the appearance of a brightly burning star. A strange variant of roses adorned the front lawn, a soft blend of red and orange petals highly contrasting the green grass that sat around them. A small spire rose above the home, with a telescope sitting atop its balcony.
"I'm gonna take a guess your family loves space," Twilight surmised.
"Considering the only pony who knows anything extensive about it is Princess Luna, it's no surprise." Sunset chuckled softly to herself, remembering the many nights she spent in that tower stargazing.
When they reached the door, Sunset raised her hoof to knock before hesitatingly slightly, then steeling herself and rapping her hoof against the door three times. Two familiar voices resounded from the other side.
"Sunflower, could you get that?"
"Okay, mom."
The door swung open, revealing a unicorn with a brilliant golden coat, a soft ginger mane done up in a braid, and green eyes. Her cutie mark was a large sunflower with blazing petals, shaped much like the flames that adorned Sunset's own mark.
The young mare gasped as she saw who was standing before her. "...S-Sunset? Is that you?"
"Hey, little sis."
Sunflower took off into the house, squealing with delight. "MOM, MOM! You'll never guess who's at the door! come her quick! You too Comet!"
She ran back to the door, an older mare and a stallion slowly following her hoofsteps. Sunflower was eagerly jumping in place as the other two made their way over.
"Sweetie, this had better be-" The older mare stopped and held her hoof to her mouth in shock. "Sunset?"
Sunset smiled sheepishly. "Hi, mom. Long time no see."
Sunset felt herself pulled into the house as her entire family embraced her in a group hug, her mother and sister having tears streaming down their faces. They stayed there for a few minutes before Sunset was finally able to take a couple steps back.
"I know I've been gone a long time, I haven't really kept in touch, and I have a lot of explaining to do, but first, I'd like to introduce somebody." She turned to Midnight, gesturing her to come forward as well. "This is my marefriend, Midnight Sparkle."
Midnight gave a slight wave of her hoof, her cheeks red from the mention of 'marefriend'. "Hi everybo- er, everypony."
Sunset's mother, a mare with a cherry coat and rose-pink mane, wiped a tear from her eye. "Well, welcome to the family, Midnight. My name is Dawn Shimmer. I'm Sunset's mother. This is her brother Comet Streak, and her sister Sunflower."
Comet, a rather skinny stallion with a light amber coat and brilliant red mane, stepped forward and extended a hoof, which Midnight carefully took. "A pleasure to meet you, Midnight. Wasn't expecting Sunset to come back home with a marefriend, but I'm happy for you two nonetheless."
Sunflower gave a small greeting as well, but seemed more preoccupied with seeing her sister again, as she bounced around Sunset asking question after question.
"Easy, Sunflower. Geez, you're acting like a little filly again." Dawn attempted to hold Sunflower in place, to no avail.
Comet shook his head at the rest of his family. "Sunset, why don't you and Midnight get settled and I'll grab something to eat."
Midnight was rather hesitant to try a 'hayburger' as it was called, but after some encouragement from Sunset and her own first bite, she was surprised at how much she actually enjoyed it. It was still unlikely that she would ever try something back home.
"So, where shall we start?" Dawn inquired. "You lost touch for about six years now, surely some interesting things had to have happened in that time."
Sunset shifted in her seat, trying to figure out where she should begin. "First, has Celestia told you anything?"
Comet spoke up next. "Only that you had begun a special brand of studies elsewhere, and even then she wasn't too keen on details. Didn't give us a progress report until about a year ago, and even then she only said that you were 'doing wonderfully'."
Sunset glanced at Midnight, who gave her a small nod, and then turned back to her family, her heart slightly sinking at the though of what she was about to do. "It's very complicated, and I can't spare all the details. You have to promise to keep this a secret, though. Princess Celestia doesn't want word getting out about my studies."
The three in question swore to secrecy, after which Sunset continued. "Where to start... about four years ago, Princess Celestia introduced to a special mirror, one that was a gateway to a parallel world. I wanted to know more, but Celestia said that when I was ready, she would tell me more about it."
Sunset paused for a moment. "When I finally went through the portal, the world I happened upon was so strange. There was no magic, no monsters, and no ponies."
"Sounds boring," Sunflower interjected.
Sunset rolled her eyes. "There were familiar faces, though, like a counterpart to Celestia being a principal of a school, and Princess Twilight and her friends were all students, though Twilight attended a school elsewhere. So, Princess Celestia tasked me with studying this world, learning as much as I can."
"I lost track of time very quickly. Days became months, then years, and its gotten to the point where I've made such a life across the portal that I don't know where my home is anymore. It became worse when magic started seeping through to the other side. It doesn't behave the same, and more often than not seems to overwhelm and corrupt those it touches.
My mission to study was overthrown by the necessity to protect the world from magical threats."
"I wish I could've kept in touch, but it's near impossible to create any sort of contact between the two realms. The only outlet to here I had was a journal to Celestia, which somehow ended up in Princess Twilight's hands."
She looked at each of her family members in turn. "I'm really sorry I was gone for so long, and that I couldn't let you know what was going on. It took a lot of convincing for me to come back for just these next few days, and I honestly don't know when I'll come back again."
Sunset felt a hoof on her shoulder, coming from her mother. "Oh, don't be like that. Sure, we were worried when we didn't hear from you directly, but Princess Celestia assured us that you were alright. and just know that whenever your mission should end, you'll always have a home here."
Comet leaned forward from his place on the couch. "So when did you meet Midnight here? I assume by the surname she is related to Princess Twilight in some way."
Midnight laughed nervously. "Well, you could say that. I'm actually her counterpart from the other side, though for some unexplained reason, my appearance alters whenever I cross over."
Both Dawn and Comet held wide-eyed looks at the revelation.
"...oh sweet Celestia, my sister is dating Twilight Sparkle! This is so cool!" Sunflower, hardly containing her excitement, started bouncing up and down on the couch.
"Enough, Sunflower," Dawn got the young mare to relax, then stood up from her seat. "Well, now that we are caught up, how about we go out and celebrate?"