After undergoing radical surgery for injuries from a motorcycle accident, a young woman (former adult film star Marilyn Chambers) develops a strange phallic growth on her body and a thirst for human blood -- the only nourishment that will now sustain her.
Darryl Revok is the most powerful of all the scanners, and is the head of the underground scanner movement for world domination. Scanners have great psychic power, strong enough to control minds; they can inflict enormous pain/damage on their victims. Doctor Paul Ruth finds a scanner that Revok hasn't, and converts him to their cause - to destroy the underground movement.
The residents of a suburban high-rise apartment building are being infected by a strain of parasites that turn them into mindless, sex-crazed fiends out to infect others by the slightest sexual contact.
After a tragic event happens, composer John Russell moves to Seattle to try to overcome it and build a new and peaceful life in a lonely big house that has been uninhabited for many years. But, soon after, the obscure history of such an old mansion and his own past begin to haunt him.