Monique is a 35 year old French woman, living in New York. The daughter of a French diplomat who has remarried, Monique has no financial worries, and holds a good job with a publishing firm. She finds relationships difficult, and frequently suffers acute depression. Her nights are filled with strange dreams, and apparitions of flashing lights.

A man discharged from the hospital after suffering a nervous breakdown is taken to a remote Italian villa by his strangely-behaving wife. But he has strong premonitions that the house is possessed by some force of witchcraft, which he has been experiencing in his recurring nightmare.