In the Diamond Ore Country lies the powerful Holy Diamond, which has served as the kingdom's source of energy and maintained the Diamond Ore Country for centuries. Many Melecie live in the Diamond Ore Country, including their princess - the Jewel Pokémon, Diancie, who created the Heart Diamond. Diancie no longer has the power to control the Holy Diamond and her country is falling into chaos as a result. One day, Diancie meets with Satoshi and his friends and asks them to go on a journey to find the Life Pokémon, Xerneas, in order to restore the Holy Diamond. Standing in their way is the Pokémon of Destruction, Yveltal, who once stole all of the life in the Kalos Region. During their journey they are attacked by the Rocket Gang, as well as the jewel thieves Marilyn Flame and Ninja Riot. They are aided by Millis Steel and her father Argus, travelers who also encounter the Cocoon of Destruction.