"Twilight?" Luna called as she roamed the castle halls. She hadn't seen hide nor hair of her for two days, and she was getting worried. "Twilight, where are you?"
As she turned the corner, she heard a loud bang and a yelp coming from the entrance to the library, where Twilight used to spend her days before she went to Ponyville. That's most likely where she is.
Luna pushed open the door and carefully made her way through the bookshelves like a skittish cat. She found Twilight in the corner, where at least four or five different chemistry kits were stacked on top of a large wooden table, along with numerous bits of metal and machine parts. The purple scientist in question was up against the opposite wall, breathing quickly. A big black scorch mark was right next to her head. She caught sight of Luna and ran toward her.
"Luna, I did it! It works!" Her expression was one of pure jubilance.
"What works?" Luna asked, stealing a glance at Twilight's lab table. A particular device caught her eye - a combination of springs and wires that currently crackled with leftover magic from some spell.
"My transistor!" Twilight tugged off her goggles, her eyes shining. "It redirects electricity, and I thought this one was going to work and so I used a mild electricity spell on it and it worked and and and-"
"When's the last time you ate?" Luna interrupted. Twilight's stomach growled, and she blushed. Luna rested a wing across her shoulders. "Let's go eat, then you can show me your transistor."