The official Pokémon website has posted the Movie 17 English dubbed prequel short Pokémon Diancie Princess of the Diamond Domain as part of the launch website for the 4th XY TCG expansion set Phantom Forces.


While on a journey to search for Xerneas, Diancie is awakened by a cry for help and goes to investigate. When Diancie's loyal Carbink subjects discover that their princess has wandered off and decide to follow, all four of them find themselves in a sticky situation!

Source: http://xy4.pokemontcgxy.com/diancie/movie-time/