Ollie

Dr. Fuji, a research scientist of Team Rocket, briefly describes in a prologue how his researchers uncovered a fossil of the remnants of Mew, one of the rarest Pokémon in existence, believed to be extinct (although this is not the case).

The film's setting is in the water-themed Johto city of Altomare (which means "High Sea"), based on Venice, Italy. The city is watched over by two legendary Pokémon, Latias and Latios.

Lucario and the Mystery of Mew opens over the foggy landscape of Rota, with Ho-oh flying overhead. Then it goes to Lucario, who is jumping from rock to rock.

Professor Spencer Hale, once one of Professor Oak's top students and a good friend of the Ketchum family, is obsessed with discovering the secret behind the mysterious glyph-like Pokémon called Unown. One day while investigating some ruins, he disappears after encountering the enigmatic creatures, leaving his only daughter, Molly, alone and lonely back at his mansion.

The story revolves around the Millennium Comet, which appears in the night sky for seven days once every thousand years. It is, at the same time, when the legendary Pokémon Jirachi awakens from a long slumber to absorb the comet's energy.

The film focuses on Celebi who travels to the future and brings with a boy named Sam when being chased by a hunter. Meanwhile Ash, Misty, Brock, Pikachu and Togepi are on their way to the next gym in their Johto journey and get a lift from a man named Maki who takes them to his hometown of Arborville.

Ash is a young boy who has always dreamed of becoming a Pokemon trainer. At age 11 he is gifted his first Pokemon, Pikachu, from Professor Oak.