An insect bites a man in a greenhouse after he touches an uncommon plant. A mysterious parasite that erupts from his lips as a huge slimy wormlike monster causes him to feel ill and be brought to an emergency room. The wormlike creature that develops to monstrous proportions after inadvertent exposure to a genetic growth stimulant and starts a reign of terror and carnage in the hospitals abandoned wing is the immediate dilemma for the hospital.