Beneath the Diamond Domain, the Heart Diamond that keeps the kingdom alive is falling apart, and Diancie, who rules the Carbink there, has not the strength to make a replacement. She sets out to find Xerneas and falls in with Ash and his friends, but thieves who want her diamond-making power follow, and the chase disturbs Yveltal where it sleeps inside its cocoon. This manga retells the film Pokémon the Movie: Diancie and the Cocoon of Destruction.