Satoshi, Kasumi, and Takeshi continue exploring the Johto region, then have to rescue Pikachu after Musashi and Kojiro kidnap him. The search leads them to the hidden plateau where Mewtwo has established a haven for the cloned Pokémon from the previous film. The evil Sakaki is plotting to recapture Mewtwo and renew his efforts to create an army of bio-engineered Pokémon. Aided by the reluctant Nyarth, Ash and his friends defeat Sakaki and his henchman.