A trainer in an underground battling circuit is deemed the perfect target for genetic Pokemon experimentation, and undergoes a detailed transition in mind and body toward his favorite species, with a sexual drive to match

A Pokemon Trainer named Evan has battled through Cerulean Cave in hopes of catching Mewtwo to bring him closer to becoming a Pokemon Master. Unsurprisingly, Mewtwo has no interest in joining his Pokemon collection and instead swaps Evan's body with that of his favored Pokemon partner, Charizard.