Pokémon: The First Movie

Pokémon: The First Movie, originally released as Pocket Monsters the Movie: Mewtwo Strikes Back is a 1998 Japanese animated film directed by Kunihiko Yuyama, the chief director of the Pokémon television series. It is the first theatrical release in the Pokémon franchise. The title can also be interpreted as Mewtwo's Counterattack.

The Pokémon Mewtwo was created in an island laboratory from the DNA of Mew, a rare Pokémon believed to be extinct, recovered from fossilized remains. Displeased with the concept of being nothing more than a mere lab experiment, Mewtwo destroys the laboratory.Shortly afterward, he meets Giovanni, the head of Team Rocket, who proposes a partnership with the Pokémon in exchange of helping it control its powers. Mewtwo is "trained" over the next few months, being pitted against challengers in Giovanni's gym and restraining Pokémon for Team Rocket to capture. Mewtwo eventually realizes that Giovanni is merely using him as a tool and destroys his headquarters.
Mewtwo reveals itself to Ash, his friends, and three other trainers who braved the storm battle as the "World's Greatest Pokémon Master," and that it had created the storm with its powers to test the trainers' wills. After being berated by Mewtwo for the relationships they share with their Pokémon, Ash and some of the other trainers challenge Mewtwo after witnessing Mewtwo's confession of having kidnapped Nurse Joy for his own personal purposes, the trainers pits their Pokémon against clones of Venusaur, Blastoise, and Charizard. The clones easily defeat the trainers' Pokémon. Mewtwo proceeds to steal everyone's Pokémon, including Ash's Pikachu, with a special set of Poké Balls; he also captures three trainers with these Poké Balls as well. Ash pursues his Pokémon as they are taken deep into a cloning facility on the island and rescues them while they are being cloned. The clones join with Mewtwo and the cloning machine explodes, releasing all the captured Pokémon. Mewtwo announces its intentions to overthrow humanity with its army of Pokémon and rule the world. Enraged, Ash lashes out at Mewtwo, who repels and blasts him away with its psychic powers. Ash is saved by Mew, the rare, playful Pokémon having appeared periodically before, who is engaged by Mewtwo. A brutal battle between the trainers' Pokémon and their clones erupts, although Pikachu refuses to fight with its own clone.