A visit to the Sinnoh region turns into a high-stakes adventure when Ash, Pikachu, and friends join forces with powerful Pokemon to confront a looming threat! When Ash, Goh, and Dawn receive a mysterious message from the Mythical Pokemon Arceus, they meet up with Brock and head to Mount Coronet to investigate. There, they find a rampaging Heatran and the commanders of Team Galactic, who are determined to find their missing leader by opening a gate between dimensions. With a trio of Legendary Pokemon and Sinnoh Champion Cynthia on their side, our heroes have lots of help, but they'll need all they can get to save Sinnoh from being destroyed!