The new film is a 3D CG remake of Pocket Monsters: Mewtwo no Gyakushū, the 1998 film adapted into English as Pokemon: The First Movie.
Masachika Ichimura is also reprising his role as Mewtwo from the original Pokemon: The First Movie.
The film’s title is a reference to Pokemon: The First Movie, which opened in Japan in 1998 with the Japanese title Pocket Monsters: Mewtwo no Gyakushū.
Takeshi Shudō (Pokemon: The First Movie) is credited as the scriptwriter, although he passed away in 2010.