To describe the plot of The Visitor is to invite skepticism. The film stars John Huston (the legendary director of The Maltese Falcon ) as an otherworldly being named Jerzy Colsowicz—a cosmic warrior who may be the reincarnation of Jesus Christ or a Jedi-like guardian from a dying galaxy. He arrives on Earth to battle an ancient evil: a mute, telekinetic 8-year-old girl named Katy Collins (Paige Conner).

The film opens in a psychedelic, ethereal dimension where a "Space Jesus" figure (played by an uncredited ) explains a cosmic conflict to a group of bald-headed children. Centuries ago, an alien criminal named Zatteen (Satan) escaped to Earth and procreated with human women, leaving a bloodline of evil descendants with telekinetic powers.