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.

Diane is a repressed, neurotic grad student, who moves into a cursed mansion only to be possessed by the house's demonic master. She is then transformed into a raven-haired, leather and lingerie-clad seductress, who seeks a virgin sacrifice for her master. Meanwhile her sister, brother-in-law, a priest, and a pizza boy try to rescue her while avoiding the demon's wrath.