Against better judgement, David buys his daughter a pony for Christmas. Too bad it was Diamond Tiara. She, like many other fillies and colts in Ponyville, was taken by Discord for his cross-dimension pony trade. Now she must convince David and his family to help her and the others get back to Equestria. Fortunately for her, David is more than happy to get rid of her. His daughter Tiffany however, is not.