In this Pokémon adventure, a mysterious force binds Ash to the Mythical Pokémon Volcanion when it falls from the sky. Volcanion can’t get away, and Ash is dragged along as it continues on its mission. They arrive in a city of cogs and gears, where a corrupt minister has stolen the ultimate invention: the Artificial Pokémon Magearna, created 500 years ago. The minister plans to use Magearna’s mysterious power to take control of the mechanical kingdom. Can Ash and Volcanion work together to rescue Magearna? One of the greatest battles in Pokémon history is about to unfold!

In a country called “Diamond Domain” lies the powerful Heart Diamond, which has served as the kingdom’s source of energy and maintained the Ore Country for centuries. Many Carbink live in Diamond Domain, including their princess – the Jewel Pokémon, Diancie, who created the Heart Diamond. Diancie no longer has the power to control the Heart Diamond and her country is falling into chaos as a result. One day, Diancie meets with Ash and his friends and asks them to go on a journey to find the Life Pokémon, Xerneas, in order to restore the Heart 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 Team Rocket, 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.