Elliot, a successful gynecologist, works at the same practice as his identical twin, Beverly. Elliot is attracted to many of his patients and has affairs with them. When he inevitably loses interest, he will give the woman over to Beverly, the meeker of the two, without the woman knowing the difference. Beverly falls hard for one of the patients, Claire, but when she inadvertently deceives him, he slips into a state of madness.

After undergoing radical surgery for injuries from a motorcycle accident, a young woman develops a strange phallic growth on her body and a thirst for human blood—the only nourishment that will now sustain her.