 Industrial spy and former FBI agent David  Mo  Rutherford is hired by executives of the ice-cream industry to disclose the recipe of the phenomenally successful marshmallow- and yogurt-like desert called the Stuff. Somehow, its consumers become addicted in the product, and competitors want the formula. With the support of Nicole, the the designer of the Stuff s advertising campaign; and a boy named Jason, who refused to eat it after his family became consumed, Mo tries to prove that the Stuff is a malevolent, possibly sentient, natural substance that is trying to take over the minds of the population of Earth.