David MacLean is a normal 12-year-old kid with normal problems until he sees a flying saucer land in a field near his house one dark night. His dad goes to investigate and doesn't return until the next morning. And there's something terribly wrong with him. He's sporting an odd mark on his neck and acting like a jerk rather than the loving parent he'd been before.

    David's mom, the local cops and other folks in town all fall prey to the same strange problem, and David teams up with beautiful Dr. Pat to try figure out what the heck is going on.

    Our heroes finally convince the authorities that Earth is under assault from extraterrestials. But as the Army strives to reach the aliens' underground base, David and Dr. Pat are captured by the hideous, 8-foot-tall creatures.

    At first the terrifying invaders seem invulnerable. But David eventually saves the day by getting his hands on a ray gun and blasting his way to freedom just before an explosive charge blows up the spaceship.