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 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.
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.