To say that this was an uncomfortable situation would have been the understatement of the century. Twilight, having just met up with her old rival, Sunset Shimmer, was now standing between her and the one pony that the latter probably never wanted to see again, Princess Celestia. The young alicorn knew all too well the kind of history these two had, and was not keen on being here to see what words would pass between them. Glancing to her left, she saw that Sunset was still looking both shocked and, to some degree, terrified at the arrival of her old teacher.

It was also a difficult situation for the formerly-human Flash Sentry, who was glancing from Sunset to Celestia, and back again. He did not know who the elder alicorn was, only that her presence was causing Sunset great discomfort right now. Twilight couldn't help but envy his ignorance of this situation. After what seemed like an unbearably long silence, Celestia finally broke it by turning her attention to the still-confused stallion.

"You are the Flash Sentry of the world beyond the mirror?"

Flash looked up at her, clearly somewhat unnerved by the elder Princess. Twilight could not blame him for that reaction. As benevolent as Celestia was known for being, Twilight knew well that she could get very commanding and imposing when she needed to be. She looked on as Flash looked to the mares on either side of him, first to Sunset and then to Twilight, before looking upon Celestia again. He said nothing, but gave a short nod. After looking upon him for a brief moment, Celestia returned the nod before stepping further inside the chamber.

"Then I must ask you to step outside for a moment. This is a private matter."

Twilight could practically feel her blood run cold at the way Celestia was saying that. After everything Sunset had done in her past, she knew what was coming. Flash looked to Sunset, still unsure about what was going on, and the mare looked back at him, her expression changing from one of fear to a more affectionate look, smiling at him and giving him a nod, as if to let him know she would be fine. Flash paused for a moment, and Twilight wondered if he might even defy Celestia and refuse to leave Sunset, which was not something she'd want to see him do. But, in the end, Flash just nodded back at Sunset before making his way out.

As he left, Twilight saw him give Celestia a rather cold look, though the latter's attention had now returned to Sunset, so she might not have noticed. Once outside, Twilight saw that Flash now stood just a few metres away from her Flash, and the two stallions looked at each other rather uncomfortably. Twilight could not blame either of them for that though. After all, she'd had enough experience with meeting another version of herself with that time travel business from a few years back, so she knew better than anypony how awkward it could be. But regardless, she then noticed that the door was now bathed in Celestia's magic and closed behind her, leaving only her, Twilight and Sunset in the room.

The young Princess wished that somepony would say something, ANYTHING, just to end this painful silence. Eventually, she got her wish, as Celestia stepped forward towards Sunset.

"Sunset Shimmer. You know your crimes?"

Twilight glanced to her left, and looked on as Sunset lowered her head, her gaze now upon the floor, before nodding her head solemnly. Celestia's eyes narrowed somewhat before she spoke again.

"When we last met, you violated my command, and entered through the magic mirror. When you returned, you attempted to steal the element of magic, and in so doing, tried to strike against the ponies of Equestria."

Celestia frowned deeply, a look that Twilight knew well whenever she herself had made mistakes.

"Do you deny these charges?"

Another silent nod was given by Sunset. Twilight nervously looked from one to the other, before doing something she knew she would regret. She spoke out.

"Princess, I think she..."

But she was cut off immediately as Celestia swiftly raised a hoof, silencing the younger alicorn, who immediately took a step backwards. With Twilight no longer wishing to dare intervene in this, Celestia carried on.

"What do you have to say in your defense?"

Twilight looked over to Sunset, who had remained staring at the ground this whole time, most likely out of shame. The silence from before returned, and Twilight grew increasingly uncomfortable with this entire situation. But eventually, Sunset finally broke that silence and raised her head, looking her former teacher right in the eyes.

"Nothing. In every way, I have done wrong. I rejected your teachings, your attempts to make me into a better person. I turned against you because of my own blind ambition and ran away because I saw you as my enemy. I took what was not mine in the hopes of subjugating entire peoples. There is no amount of good that I can do in this lifetime to make up for that."

As Sunset spoke, Twilight could hear her voice wobble, as though on the verge of tears. But all the while, Celestia was looking down on the young unicorn, her face as difficult to read as ever, and Twilight wondered what the elder Princess might have been thinking. Looking back at Sunset, Twilight saw that she was looking down at the ground once more.

"I am guilty. Do what you wish of me."

Twilight was, needless to say, astounded that Sunset was so ready to accept judgement over her actions. When she'd first met this mare, there was no way in Tartarus that she'd have ever been willing to go through something like that. And now, here she was, taking responsibility for everything she'd done. Twilight had never actually witness Celestia administer punishments for the kinds of crimes that Sunset had committed, nor was it something she'd ever wanted to see. But now, it seemed she would have to, as her former teacher stepped forward, Sunset clearly struggling against the urge to cower away from her. Once she was only a foot away from her, Celestia spoke.

"Sunset...look at me."

The unicorn's legs seemed to shake as her head slowly looked up, and she saw Celestia' eyes peircing into her. It was a sight that would have sent shivers down the spine of even the bravest of ponies, but Sunset endured it nevertheless. The Princess of the Sun looked down at her one-time pupil, right int her eyes. She scoured them, looking deep, as though trying to read her very soul, but even so, Sunset kept looking at her as asked. Time passed and, to the shock of both Twilight and Sunset, Celestia not only let out a sigh, but her face broke into a small smile, and she raised her hoof and placed it on Sunset's shoulder.

"I forgive you."

Twilight's eyes widened with disbelief over the words she'd just heard. Looking over to Sunset, she could see that her shaking had stopped, and instead she seemed petrified, as though frozen by the sheer shock of this moment. But her face was bearing a look of utter confusion, as she looked up into Celestia's face, trying to see if perhaps this was some kind of joke. But there was no trace of deception of the Princess' eyes, only truth. Sunset's mouth opened and closed several times, a clear sign that she had difficulty in figuring out what to say after this, for which Twilight could not blame her.

Eventually though, Sunset finally managed to get her words together.

"But...why? How could you POSSIBLY forgive me after everything I've done? I was your enemy! I betrayed your trust, your teachings! And you...you're just going to forgive me?"

Celestia, still smiling, nodded at that.

"Yes, I am. You have made many mistakes, Sunset. But I can see you have changed. You've recognised what you once were, and what you've done, and were even willing to return to this world to pay for those actions. The Sunset who turned against Equestria would never have done that."

During this exchange, Twilight was deep in thought, and in doing so, she realised that it was not perhaps so far-fetched that Celestia would do this. While it was true that Sunset had committed a great wrong in her time, she was not the first. After all, it was not so long ago that Celestia was willing to welcome back the Lord of Chaos himself, despite all the years of misery he'd inflicted on the ponies of Equestria all those centuries ago. If Celestia could forgive him, she could forgive Sunset. And speaking of whom, Sunset looked up at her old mentor, still not believing what she was hearing. Celestia's smile grew even wider.

"Welcome home."

It was in this moment that the floodgates finally opened. Sunset's face, though initially looking as though she was fighting to hold back the tears, now simply let them flow down her cheeks. She charged forward and wrapped her hooves around Celestia in an embrace. Twilight looked on as she could hear her former enemy let out sob after sob as she buried her face into Celestia's chest. The Sun Princess knelt down on all four hooves as Sunset did this, spreading her wings forward and using them to return Sunset's embrace. As this was going on, Twilight could hear Sunset speak, as the tears kept on coming.

"I'm sorry! I'm so sorry! I'm sorry for EVERYTHING!!!"

But Celestia merely looked down at her, with a warm and comforting expression. As Twilight looked upon the two of them, she thought back to her own tutoring by Celestia, how there came a time in her life when she viewed the Sun Princess as a second mother. It dawned on her then and there that this may well have been how Sunset once saw her, a relationship that had been poisoned by the latter's once-fierce ambitions and bitterness. But now, after all the hardships that had occurred between these two, including an exile that had taken up much of Sunset's life, Twilight smiled to see that the great rift that once separated these two had healed, as Celestia's words made clear.

"It's alright, Sunset...I've missed you."