"Books."
Twilight had been searching through her library for the past seven hours. She wanted to find an old book that Celestia had shown her while younger. It talked about traveling through dimensions, but she had ignored it when younger as all of the info written into it had been theoretical and hypothetical.
But now after going to another dimension through a mirror and seeing the past and present getting changed, she felt it could be useful. And she was pretty sure that Celestia had given her that book. Now she only needed to find it. Unfortunately she had forgotten the title of said book. She also didn't know what she was going to do with that book.
It was mostly out of curiosity to be honest. Celestia's teaching, which were mostly lessons about what not to do, meant she knew what kind of magic Trixie had used. So she had a faint hope that the book could give her some useful information.
But that would require Twilight to find the book first. If she couldn't find it then she would have to ask Celestia if she remembered it. Because maybe Celestia hadn't send it to her. The only thing Twilight remembered was it's fairly silly cover picture.
"Twilight?"
Twilight was suddenly pulled out of her thoughts by Spike. She couldn't ask Spike for help as she didn't know how to properly describe the book. "Yes Spike?" Spike had entered the room. "Applejack needs your help with something." He said. Applejack then entered the room.
Twilight put the book she was currently holding onto a neat pile. She would continue searching later. After quickly greeting each other Applejack started explaining her problem. Twilight found it quite strange, but it wouldn't take too long to solve.
Twilight had quickly solved Applejacks problem. It actually was a nice break. But now back to searching for a book, for a few more hours. For once she wasn't excited about the idea, because of how vaguely she remembered it. She did find a few other interesting titles. She was also getting tired as it was already night.
The multiverse, Theories of the multiverse, dimensional travel?, barriers and limits and other titles like that. She had read some of the more interesting ones. All of them were either about theoretical science or were just nonsense made by someone with too much time on their hands. She might have to check the Manehattan and canterlot libraries for any more reading material. Hopefully written by an actual scientist.
Twilight mindlessly picked another book out of the book racks, sipping out of a cup of coffee. She stared at it without much thought, not having much hope in the book being interesting or useful.
She spat the coffee out of her mouth as she stared at the cover. "Found you."