Celestia took a few, slow, tentative steps towards Twilight and Sunset. “It's... good to see you again,” she finally said, stopping a couple of feet away from the two. She canted her head from side to side. “You've grown wings.”
Sunset's gaze shot down once more to the floor. “Yeah. Twilight told you about the Sirens, right? Battle of the Bands?” She looked to her sides, her wings extending. “I didn't know about it until crossing the-the mirror back into Equestria. Still kinda waiting to wake up from this great dream, to be honest.”
Celestia's eyes shone a bit. “I know the feeling. You've come a long way and done so much, Sunset.”
A tiny smile graced Sunset's lips. “I had a lot of help along the way, Princess.” She glanced at Twilight, still by her side. “They didn't have to, but they did. Part of me still isn't sure why. I was horrible.”
Twilight draped a wing over Sunset. “Don't dwell on the past, Sunset. Learn from it, but don't let it overshadow everything you've accomplished. And it's a lot!”
Celestia nodded. “Twilight's right, Sunset. I know–”
“Princess, wait,” Sunset said, taking a few steps forward, away from Twilight. She craned her neck his and, with some effort, locked eyes with her former mentor. “There's something I have to say to you. It's very important. May I?”
Celestia's jaw slowly closed. She bowed her head and took a step back, waving a wing at Sunset.
Sunset sucked in a deep breath. “I am... I am... so sorry,” she finally said, her voice breaking at the end. Sunset's eyes watered and tears started sliding down her cheeks, but she kept her head high. “You gave me love, an education, knowledge, patience, understanding and I balled it all up and t-threw it back in you-your face. I was horrible to you, my family, to pretty much everyone at the school. To say I was a horrible brat is the understatement of year.” At that, she finally broke eye contact with Celestia. Her eyes closed and the crying increased. “I'm sorry, I'm sorry...” she repeated, her shoulders heaving up and down.
Celestia closed her own eyes and shook her head. She stepped right up to Sunset's side turned herself around, and lowered herself to her haunches. She extended a wing and draped it over Sunset, pulling her in close. She waited until Twilight was also by Sunset's side before speaking. “No, Sunset, no. Don't do that to yourself. There's a big difference between sincere regret and self-loathing. It's a line I'm quite familiar with.”
Sunset sniffed and wiped her now-bloodshot eyes. “But what I did–”
Celestia shook her head. “What you did was... ill-informed, Sunset. Not the best actions, but you weren't alone in culpability. As your teacher, I should have done more to help and guide you.”
Sunset's head slowly turned in Celestia's direction. “Princess... you did everything you could have to help me. It's not your fault I rejected your teachings, nor did you have anything to do with what I did at Canterlot High! That was all me.”
Celestia tilted her head from side to side. “I still bear some responsibility, even just as your teacher. That is the truth, Sunset.”
Sunset's head dropped, but she remained silent.
Celestia continued. “It speaks well of you to remember past faults and mistakes, so long as you learn from them and use them to better yourself, which it seems you did,” she said, winking. Her expression once more turned serious. “However, if you dwell on them too much, they can consume you.”
Twilight cleared her throat, getting Sunset's attention. “I have some... experience with that happening to someone here, Sunset. It wasn't pretty, to say the least. Celestia's right. You've done some wonderful things, made some great friends and have saved your adopted world.” She leaned in close to Sunset. “And don't you ever forget that.”
Sunset bit her lip, but the corners of her mouth still turned up. She looked to Celestia. “I... I will try, to focus on the good a bit more, especially around you. Thank you.”
Celestia drew Sunset in closer, leaned down and nuzzled her. “We've all made mistakes or missteps, Sunset. It's how we deal with them that's the most important thing. So, how will you deal with yours?”
Sunset glanced down. “I guess... try to keep them in mind? Learn from them, like you said?”
Celestia nodded. “An excellent lesson learned, Sunset.” She stood up, Twilight, and eventually Sunset, following suit. She reached out with a foreleg and pulled Sunset in for a quick hug. “I really am proud of you, defeating the Sirens. Twilight told me all about it.” She looked Sunset over. “She forgot to mention you ascending,” she said, winking.
Sunset barked a laugh. She stretched her wings out. “A surprise to the both of us, Princess.” Sunset leaned into Celestia, a smile quite visible now. “Thank you. It was really close for a bit. If it wasn't for Vinyl Scratch showing up when she did...” Her eyes closed as she shuddered.
Celestia's horn glowed. A table, two chairs, and a complete tea set popped into existence near the cutie map. “Well, I'd love to hear about it straight from you. If you don't mind, that is?”
Sunset trotted over to the table. Her horn glowed and one chair slid out, but she suddenly stopped. “Wait...” She slammed a hoof onto the floor, sending out a small tremor. “I can't, at least right now.” She held a hoof up and motioned to the door. “I told Trixie I'd call her tonight and arrange for her to bring several discs with very valuable information over here for Captain Kirk and Captain Kang.” She hung her head. “As much as I'd love to, Princess, I can't put this off. Lives are at stake!”
Celestia's brow furrowed. “Sunset, I'm afraid I'm not following you. What are these discs, and how can they contain any sort of information that could help Captain Kirk or Captain Kang?”
Twilight shot to her hooves and trotted over to Celestia's side. “It's... really unbelievable, Celestia, but also really true. You see, there's... there's...” She turned to Sunset and waved a wing at her. “There's something Sunset needs to explain, because I'm still not sure how.”
Sunset glared at Twilight for a moment. “Thank you very much, Twilight.” She focused on Celestia once more. “All right, over in that reality, as insane as it sounds, the missions of the Enterprise, and the whole Federation? It's a series of fictional adventures across the mirror.” She launched into a rather abbreviated explanation about the 'Star Trek' television show and franchise overall, focused on the first two shows. Her horn lit up and various images appeared, of the Enterprise, of some of the cast, and even a brief snippet of the action.
Celestia remained quiet through Sunset's explanation, only nodding occasionally. At the end of Sunset's explanation, she finally spoke. “And you told all this to Captain Kirk and Mister Spock?” At Sunset's nod, she cocked an eyebrow. “They seemed fairly calm before beaming away.”
Sunset shrugged. “Compared to some of the horse apples they faced, this is kinda small potatoes. I mean, they already have experience with alternate realities from the episodes 'Mirror, Mirror', and 'The Tholian Web'.”
Celestia rolled her eyes. “I'll take your word on that, Sunset. But in all seriousness, when it comes to trying to change the timeline, care must be taken. Even the best of intentions may lead to disaster down the way.”
Sunset looked down at the floor. “Off the top of my horn, two good men will lose their sons without this information, Princess. If there's a chance to prevent at least that, I must take that risk.”
Any seriousness in Celestia's expression vanished. She slowly lowered her head and gently nuzzled Sunset. “I am very proud of you for how far you've come, Sunset.”
Sunset's body froze for a moment, but she eventually returned the nuzzle. “Thank you.”
Twilight walked up to Sunset and cantered around to her side. “So back now, or later?”
Sunset waved a wing at the door. “As much as I'd love to stay, have tea, meet your friends, see my family...” She paused and swallowed down a rising tide of emotion. “No, no. I can do that later. Tomorrow, after Trixie and I lend Mister Spock the discs.”
Celestia nodded. “We're going to hold you to that,” she said, winking.
Sunset grinned and barked a laugh. She trotted to the door, horn starting to glow, but it opened before she reached it. She slowed to a halt as Spike walked in, wearing an apron, chef's hat, and a tray of cookies in his claws.
Spike held the tray out. “Okay, I know what I said before leaving is usually a bad excuse to get out of an awkward situation, but I figured cookies couldn't hurt anything.”
Sunset floated a cookie up and over to her mouth. She took a bite, then finished it off with two more. “Spike, you are one great dragon. A great cook, too.” She floated two more off the tray, scarfing them down quickly.
Twilight and Celestia floated some cookies towards them, eating them. The glow around Twilight's horn brightened as she floated Spike himself over to her. She placed him on the ground in front of her and wrapped both forelegs around him in a hug. “This was very thoughtful of you, Spike. Thanks.”
Spike returned the hug, then slipped out of Twilight's grasp and rubbed his claws against his chest scales. “Well, I try. You're welcome.” He looked around. “So... things work out?”
The three alicorns all exchanged a glance. “I think things have worked out just fine,” Sunset said, as all three smiled.