On its way back to Earth, the space shuttle Nautilus passes through a cloud of alien spores causing its sole occupant, astronaut Steve Thomas to transform into a blood-thirsty monster. The shuttle crashes into a swampy region of central Florida, creating a situation which threatens contagion and/or death to all who encounter the shuttle or its mutated pilot.

Triton Indutries has created a genetically-engineered creature using DNA from human sources. During the course of the experiment, however, the host mother carrying the mutant escapes from the laboratory compound, giving birth shortly thereafter. The intellient "baby" beings hunting down and killing its male DNA donors, while at the same time trying to mate with its female donors. The head of the lab wants to destroy the monster before the press can get wind of the story, but the former head of security wants to expose the whole thing.

Clay Doyle, a drifter haunted by the ability to see violent events from the past, wanders into a small Florida town and falls in love with the ethereal Sarah Miller, despite increasingly disturbing visions of murder and decay.