Rudolf, a black stray cat, is suddenly separated from his beloved master. He unexpectedly wakes up in a long-distance truck that takes him to metropolis Tokyo. There, he meets Ippai-attena, a big boss cat feared by everyone in town. Unable to return home, Rudolf starts a life as a stray with Ippai-attena, but Ippai-attena isn't all that he seems to be.

After accepting an invitation from a mysterious trainer, Ash, Misty and Brock meet Mewtwo, an artificially created Pokémon who wants to do battle.