"Spike take a letter." Twilight said the next morning.
"On it," he said as he took a piece of paper and a quill, holding both expectantly.
Twilight smiled softly, "Now, could you give those to me?"
Spike raised an eyebrow, "But I need these to wri– oh," he said, taking the hint that this was going to be private. He then obediently handed the writing materials over. Twilight thanked him and walked upstairs to her room as he continued looking expectantly. He knew that this letter must be very personal considering the trust that the two shared.
"Dear Princess Celestia,
It has come to my attention that the portal at the Crystal Empire will open in a few days. I would ask for your permission to take this opportunity to once again travel to the Mirror World and, for lack of a better phrase, see how everyone is doing. I trust your judgement and hope that you will answer expeditiously."
Celestia read over the letter a few more times and gave a sigh that wasn't frustration, but wasn't quite accepting either, she knew that everypony should forget about the mirror world; she didn't like the danger of upsetting the balance of reality here or there. And yet, she kept it there in that dark room for some reason either unknown or, more likely, denied by her. She also knew that she couldn't say no. "Very well," she thought, Twilight would be allowed to go, and then she would get rid of the mirror.
"My Dearest Student,
You will be glad to hear that I hereby grant you the permission to once again explore the human world under more favorable conditions. I would like you to take a few notes about this world as well, the small amount of information you have provided our scholars here are of great interest. Now, you should know that the portal will only stay open for ten days, though I imagine that will be plenty of time for you to do as you like. I will not be able to see you off, but I wish you safe travels.
Twilight scrutinized the space below the last line, not only did the letter end abruptly, but it seemed that Celestia attempted to remove some lettering at the end. She put that at the back of her mind; she had to prepare for the trip.
"Spike," she called, "I'm going to be out for about nine or ten days."
"Come again?"