Twilight Sparkle summons Fluttershy and Pinkie over when she has a new spell that should let her see into different realities. She wants to see if there was really an endless number of possible realities. Pinkie ends up having Twilight royally mess up the spell; it gets overcharged and switches their Fluttershy for a different reality's Fluttershy.
Both Fluttershys have to adjust to their new lives, all while Twilight tries to find a way to switch them back.
Co-written by Poison Cure
Edited by Lathier