In the days before it was common knowledge that moon monsters didn't exist, this sort of picture ran rampant. Again those dastardly moonmen try to take over planet Earth. This time, however, they have a compelling plot. In a precursor to NIGHT OF THE LIVING DEAD, the aliens take over the
bodies of dead earthlings and nearly conquer the world before Agar saves the day. He comes up with a machine that emits high-frequency sounds to drive the aliens back to their own turf. Carradine has a small role as a dead scientist who leads the zombie forces out of their graves.