Adventure on Treasure Island

There's so much to explore in Alola! Ash and Pikachu are visiting one of the tropical islands off Melemele's coast. There they discover all sorts of new and interesting Pokémon. But these new Pokémon can be a bit tricky! Can Ash and Pikachu rescue a mysterious Alolan water-type ... and persuade a mischievous new Pokémon to join their team?