This movie isn't very long but it is quite painfully entertaining. After Carradine's character blows himself up in an “atomic accident,” his invisibly invaded corpse looks up his old friend and fellow scientist Dr. Penner to deliver a message. OK.. it was more or less a monologue, but essentially invisible invaders took over the moon 20K years ago (it must have been much nicer back then) and now they have finally gotten to setting their sights on Earth! They have asked Penner to warn the people of Earth that invasion is imminent and that humanity should just simply surrender. Of course, nobody listens to the guy who talks to his recently “blowed-up” buddy, and the invisible invaders invade anyway by taking over corpses, blowing up bridges and dams, causing motor vehicle accidents, and generally causing mischief and destruction...all with the clever use of stock footage. Enter John Agar's character Major Bruce Jay who squirrels the main characters away in an underground bunker to search for some defense against the invaders. After about 20 minutes of shenanigans and pseudo-science, it is determined that the invisible invaders are highly irritated by certain sound frequencies. They then enlist Spinal Tapp to come in and turn everything up to “11!” Ok, maybe not, but it would have made for a more interesting plot than Agar riding around on top of a SUV and shooting his “screech” gun at everything that invisibly moves. The invaders are “sound waved” into defeat and the saviors of humanity are brought to the United Nations to receive thanks from a grateful planet. The (rather pitiful) end...