A trailer for the English version of the seventeenth Pokémon movie, titled Pokémon the Movie: Diancie and the Cocoon of Destruction, has been released on the official Pokémon YouTube channel. The movie features Ash and his current companions along with Pokémon from the X & Y video games, including the legendary Xerneas and Yveltal.
Here’s the official synopsis from Pokémon.com:
In the underground Diamond Domain, where many Carbink live, the Mythical Pokémon Diancie serves as ruler. The Heart Diamond that sustains the land is beginning to fall apart, and Diancie is not yet strong enough to create a new one. While seeking help from the Legendary Pokémon Xerneas, Diancie encounters a group of thieves who want to take control of its diamond-producing power—and who awaken the Legendary Pokémon Yveltal from its cocoon in the process! Can Ash and his friends help Diancie discover its true power, stop Yveltal’s rampage, and save the Diamond Domain?
A release date has not yet been confirmed.