While putting their hero skills to use on the peaceful island of Nabu, the Class 1-A kids face a sudden attack from a formidable villain known as Nine.

All Might and Deku accept an invitation to go abroad to a floating and mobile manmade city, called 'I Island', where they research quirks as well as hero supplemental items at the special 'I Expo' convention that is currently being held on the island. During that time, suddenly, despite an iron wall of security surrounding the island, the system is breached by a villain, and the only ones able to stop him are the students of Class 1-A.

This is the story of how Ash and Pikachu first met. At first, Pikachu was disobedient towards Ash, but Ash only wanted to be friends with Pikachu. On the day they set out from Pallet Town, both of them saw a Ho-Oh flying and they made a vow to meet it.

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!