A Martian invader crashes his spaceship conveniently close to the workshop of a scientist who is developing an interplanetary craft. If the extraterrestrial Purple Monster can complete the rocket ship and return to Mars, he will be able to start a full-scale invasion of Earth. Good thing Craig Foster sets out to thwart the Monster's mission!
as The Purple Monster
as Craig Foster
as Sheila Layton
as Dr. Cyrus Layton
as Hodge Garrett
as Marcia
as Emperor of Mars
as Carl Stewart
as Saunders
as Dr. Paul Meredith
as Charles Mitchell
as Helen
as Dr. Harvey
