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 diamondproducing 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?