While visiting his sister Twilight at her home in Ponyville, Shining Armor is accidentally transformed into a little, blank flanked filly. In order to hide her mistake while she tries to find a solution, Shining Armor must live as Twilight's little cousin Gleaming Shield. Things get worse when the Cutie Mark Crusaders meet the new filly and decide she needs to join their group in their adventures around town.

Thanks to DDRMASTERM for taking the time to edit the story

Takes place after the episode "Keep Calm and Flutter On" while Fluttershy believes that Discord is truly reformed, Rainbow Dash remains skeptical.

Edit: I have fixed most of the spelling and grammar errors that I could find and extended the story a bit so, hopefully it'll make a bit more sense.