After her husband is killed in a car accident, Nancy Henninger rents out her backyard apartment to try to make ends meet. But her teenage son, Zak, is suspicious of her new tenant, Harry Longworth. As well he should be. Harry says he has come to the suburban community of Hunterville to set up a new factory for his company. In fact, he's really going around town, accompanied by his partner, Parker, and quietly turning people into puddles of green slime with some sort of strange-looking ray gun. As Det. Frank Dayton looks into the disappearances, Zak conducts his own investigation. Planting a bug in Harry's room, he listens as the pair discusses their mission, and hears Harry and Parker refer to their next target. When he investigates further, he makes a shocking discovery when he comes across a list of names of the three people who disappeared. And the next name on the list is Nancy Henniger - Zak's mother!