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