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 pair of Siamese twins are separated and one is forced to live a sheltered existence under the watchful eye of a controlling psychiatrist.

Inquisitive journalist Grace Collier is horrified when she witnesses her neighbor, fashion model Danielle Breton, violently murder a man. Panicking, she calls the police. But when the detective arrives at the scene and finds nothing amiss, Grace is forced to take matters into her own hands. Her first move is to recruit private investigator Joseph Larch, who helps her to uncover a secret about Danielle's past that has them both seeing double.