Cancer-terminal tycoon Peter Murdoch's secret Wexel Hall Pharmaceuticals lab has developed a blood orchid extract cure. To examine why it works optimally in snakes, they also bread a super-anaconda strain. But the original pair escapes, leaving a bloody trail of corpses. Murdoch runs, instructing his staff to clean up. They keep failing and being eaten like unsuspecting locals, some alive, even after enlisting ruthless big game hunter Hammett. The fast-growing pregnant monster sheds its skin, thus disabling the only tracking device.

An American girl, Isabella, sets out to make a documentary to understand what happened to her mother who murdered three clergy people. She was not convicted due to insanity and was sent to a mental hospital in Italy. Isabella meets with some priests in Italy who explain that her mother's condition may not be medical, but could be an extra-human possession.