Gekijôban Poketto Monsutâ Adobansu Jenerêshon: Myû to hadô no yûsha Rukario

In the distant past, a legendary hero named Arlon, with the help of his aura-guiding hero Pokémon Lucario, senses a threat of war in front of Oldoran Castle in Kanto that would leave no survivors. Lucario transfers this message to his master, Arlon, while he is being attacked, but Arlon seemingly betrays him as he proceeds to leave, sealing Lucario away in his staff. Over a thousand years later, Ash Ketchum and his friends arrive at Cameron Palace where a festival is being held to celebrate Arlon, and Ash discovers that he has inherited Arlon's staff, which inadvertently releases Lucario from his capture.