What is the English subtitle of the first Pokémon film, released in 1998?

The English subtitle of the first Pokémon film is Mewtwo Strikes Back.

The film’s full English title is Pokémon: The First Movie—Mewtwo Strikes Back. It was released in Japan on July 18, 1998, and later reached North American cinemas on November 12, 1999. The story centers on Mewtwo, a genetically engineered Pokémon who challenges human ideas about identity and creation.

Ash, Misty, and Brock are invited to New Island by a mysterious Pokémon Trainer. The invitation leads to a confrontation involving Mewtwo and cloned Pokémon. The film also includes the short feature Pikachu’s Vacation in its theatrical presentation.

The Power of One is the subtitle of the second Pokémon film, released in 1999. Spell of the Unown belongs to the third film, so both are plausible but incorrect answers for the franchise’s first movie.