A man obtains an insect bite while working in a greenhouse after handling an exotic plant. He falls ill immediately and is sent to the emergency department, where physicians diagnose him with an unknown bacteria and a bizarre parasite that erupts from his lips as a giant slimy wormlike monster. There are soon to be additional cases of bacterial illness, but the hospital's immediate concern is the wormlike creature that grows to monstrous proportions after being accidentally exposed to a genetic growth booster and begins a reign of terror and carnage in the hospital's abandoned wing.