After teenagers Steve Andrews and his girlfriend Jane Martin see a meteorite crash nearby, they set off to investigate. They come across an old man who seems to have some type of gelatinous matters stuck to his hand. They take him to Dr. Hallen who isn't sure what the substance is but Steve becomes convinced it's a monster of some sort after both the old man and the doctor vanish. As the creature consumes more and more people, it grows larger and larger. Steve's biggest problem is that he can't get anyone to believe him and continually faces skeptical policeman and angry parents. The creature finally reaches a size that it cannot be missed and everyone wonders how they will possibly stop it.