The franchise's eighth installment is highlighted in the film. A festive occasion is held in Lohta to pay homage to "Aaron the Wave Leader Hero," a legendary figure who allegedly utilized the "Tree of the World's Origin's" powers to end a historical conflict. Satoshi and Pikachu win the hero competition, earning the prestigious title of "Wave Leader Hero." At a luxurious ball in their honor held at the castle, an apparitional Pokemon called Mew suddenly snatches Pikachu. Meanwhile, Satoshi encountered the Wave Leader Pokemon "Lucario" after its release from captivity. As Satoshi journeys with Lucario to retrieve Pikachu, he is compelled to unravel the secrets connected to the Wave Leader mythology and Lucario's shadowy past that also involves Mew.