Diamond Ore Country.
A beautiful land located deep underground, where the "Jewel Pokémon" Melecie live in peace and prosperity.



In this country, a giant diamond known as the "Sacred Diamond" can be found. For ages, the Sacred Diamond has played the role of an important energy resource, which keeps the ore country going. The only being with the power to create this type of diamond is princess Diancie herself. However, Diancie currently does not possess this power.



Time is starting to run out. The Sacred Diamond's lifespan is about to run out. When that happens, the beautiful ore country is going to perish! Having encountered Satoshi and Pikachu, Diancie sets out on a journey to save her country; a journey in search of the "Life Pokémon" Xerneas, seeking its sacred power.



On their way, they get attacked by both the female thief Marilyn, the ninja thief Riot and the Rocket Gang, who all seek Diancie's powers for themselves.



They overcome these ordeals with some help from a girl named Miriss and her father Algus, and continue onwards, however, a cocoon lies in wait for them... a cocoon where the "Destruction Pokémon" Yveltal, which is said to have once eradicated all life in the Kalos region, sleeps....



A major crisis is approaching!! Will Diancie manage to save her country?
And what will happen to Satoshi and Pikachu!?