This intriguing murder mystery has enough plot switches to keep most audiences guessing. Morgan, a widow living alone in her Paris apartment, watches the promiscuous affairs of a female neighbor. One evening she witnesses the girl's strangulation and then is forced to let the murderer,
Andreu, hide out in her apartment. She soon becomes Andreu's lover, but unexpectedly falls victim to a blackmail plot. She pays out her entire savings to keep the blackmailer from revealing the identity of her guest. Then, she learns that the "dead" neighbor is very much alive and actively
involved in the blackmail plot. To get back at Andreu, Morgan pretends that another blackmailer...